To better understand the mechanics of how [i]Trade Routes[/i]' various features are implemented, it is helpful to first understand how price and supply levels are categorized.

[i]Trade Routes[/i] has five possible price/supply levels can that be assigned to each item in each region. In terms of merchant supply, these levels could be called Plentiful, Common, Average, Uncommon, and Rare; but in terms of price, the scale is reversed: Lowest, Low, Average, High, Highest (that is, the Lowest price corresponds to the most Plentiful supply). In order to more clearly convey both the price and supply implications of the five levels, a third set of terms are used which are based on the "trade balance", or the ratio of supply to demand: Origin (highest supply/lowest price), Supply (high supply/low price), Balanced (average supply and price), Demand (low supply/high price), and Destination (lowest supply/highest price).

Most items only have one Origin region, two Supply-leaning regions, two Demand-leaning regions toward the other end of the province, and one Destination which is furthest from the source. Within Skyrim proper, this leaves three holds at the Balanced trade level. Some of the more common items have no particular Origin or Destination, but the 1-2-3-2-1 pattern is the usual arrangement. This also implies that there is usually only one route on which a given item can realize its maximum profit margin, by taking it from its single Origin to its single Destination. These routes become profitable with only two perk points in Haggling (doable at level 3) and are referred to as "long routes" because the Origins and Destinations tend to be on nearly opposite ends of the province. Long routes for various items are arranged in a continuous loop (the "long loop") that visits every hold except Whiterun, and can optionally also incorporate new regions added by supported mods.

There are also usually 2-4 routes on which a given item can realize its second-highest profit margin, either by taking it from its single Origin to one of its high Demand regions, or from one of its high Supply regions to its single Destination; these are the "short routes" because they can sometimes have endpoints in neighboring holds, and indeed there is a "short loop" of such routes that visits every hold including Whiterun. Although each route on this loop yields a smaller profit margin than a long route, they are also much shorter and so at modestly high skill, perk and equipment levels this actually allows for a higher profit-per-hour than the long loop.

As a concrete example of how these categories are applied, consider Black Briar Mead. Its Origin is clearly in the Rift, home of the Black Briar Meadery. The neighboring Eastmarch and Whiterun holds also have a healthy Supply, while the Demand is relatively high in the distant Haafingar and Reach holds, as well as Falskaar and Wyrmstooth (if installed). But the single best Destination for Black Briar Mead is the Pale, owing to its particular combination of remoteness (which would limit supplies of imports) and bleakness (which increases demand for mead). Thus the highest potential profit on Black Briar Mead can be found on the long route from the Rift to the Pale, which is indeed one leg of the complete "long loop." Likewise there are at least four potential short routes here: Rift-Haafinger, Rift-Reach, Eastmarch-Pale, and Whiterun-Pale. None of these are particularly short trips, however, and indeed none of them are part of the overall "short loop" (the Rift has a good Supply of something else with a neighboring Destination).

Price and supply patterns are not always static, however; when the player completes quests that involve the supply or demand of some type of item, that can have an effect on the regional prices and availability applied by [i]Trade Routes[/i]. Returning to the Black Briar Mead example, there is a quest that can end with the Black Briars taking over the Honningbrew meadery. If this quest is completed then Whiterun will become a second Origin for Black Briar Mead with high supply and low prices to match the Rift; at the same time, however, the price of Black Briar Mead will rise globally due to reduced competition, and Honningbrew Mead will become impossible to buy, driving its value up for any bottles left in circulation.

Because of these dynamic effects, not all of the possible long or short trade routes will actually be profitable at the beginning of the game. An aspiring trader may therefore have to get their hands dirty liberating a few mines to open up profitable trade opportunities, although this requirement can be disabled in the options.

All of the above is explained (in slightly more vague, in-fiction terminology) in the book "Ten Truths of Trading" which can be found randomly in the world or at general goods merchants. Various traveling merchants (not all of which are still alive) also keep journals which contain clues about which regions might be ripe for importing or exporting particular kinds of items; 10 of these journals cover all the long and short routes across mainland Skyrim, and there can optionally be one more each for Solstheim, Falskaar and Wyrmstooth to bring the total to 13.

[b][u][color=cyan]MAIN FEATURES AND OPTIONS[/color][/u][/b]

[i]Trade Routes[/i] has a number of core features which work in concert to make merchant inventories regionally appropriate and allow for the long and short trade loops to be profitable at appropriate times. Most of these features can be tuned or disabled from the main panel of the SkyUI/MCM menu, although the default settings are designed to work well together and should be suitable for most users.

[center][url=https://i.imgur.com/CBWZgLG.png][img]https://i.imgur.com/0vzR0LH.png[/img][/url][/center]

[b][color=yellow]Regional Supplies[/color][/b] - This feature disables the vanilla leveled item lists which provide merchant stocks for affected items (except spell tomes) and enables [i]Trade Routes[/i]' alternative regional lists. If this is disabled then merchant stocks will no longer vary by region, but you may need to disable it temporarily if you absolutely need to buy an item that is added by another mod which is not supported by [i]Trade Routes[/i]. Note that [i]Trade Routes[/i] merchant supplies are always de-leveled; the items that a merchant has for sale depend only on their specialty, their location, and current events (i.e. infested mines), not on the player's level.

[b][color=yellow]Trade Supply[/color][/b] - Even if an item can be bought for less in one hold than it sells for in another, that alone is not sufficient to enable profitable trade; in order to actually capitalize on that differential, the player needs to be able to buy a sufficient quantity of the item to yield a worthwhile profit on the other end. This feature guarantees a reasonable minimum supply for all items that are part of the long or short trade loops; by default, 1000 gold worth.

[b][color=yellow]Extra Gold[/color][/b] - Just like the above, in order to profit from a trade route the player needs the merchant at the destination to be able to afford to buy the shipment. This feature adds some extra gold to all merchants; by default, 750 gold.

[b][color=yellow]Book Supply[/color][/b] - This feature adds (by default) 6 random common books for sale at all general goods merchants. This is partly because it seemed like they should have had some in the first place, and partly to make it easier to find the book "Ten Truths of Trading" so that new players can learn how to fully enjoy the mod in-game without having to read this external documentation.

[b][color=yellow]Regional Prices[/color][/b] - This feature applies [i]Trade Routes[/i]' regional adjustments to the base value of food, drinks, animal parts, ingredients, ores, ingots, gems, soul gems and spell tomes. Whenever the player crosses a hold border (or reloads a saved game), the mod will automatically update all affected prices; this usually only takes a few seconds, but a warning will be displayed if the player is able to open a barter window before the regional update is complete. If you're having serious script lag issues and only care about the regional merchant inventories then you can turn this off, but that will of course make it impossible to profit from any trade routes since all prices will be the same everywhere.

[b][color=yellow]Price Anchor[/color][/b] - This feature essentially controls whether items are on the whole more or less expensive than vanilla; specifically, it sets the [i]Trade Routes[/i] price level at which gold values will be the same as vanilla. If the anchor is "bottom" then items will have their vanilla values only at their Origin and their value everywhere else will be higher than vanilla; if the anchor is "low" (the default) then most items will have their vanilla value in two holds, be cheaper than vanilla in one hold (the Origin) and more expensive than vanilla in the other six holds; and so on.

[b][color=yellow]Minimum Food Price[/color][/b] - Because Skyrim has no unit of currency smaller than a whole gold Septim, [i]Trade Routes[/i] could not possibly apply a 50% regional discount or markup on an item with a base value of 1 gold. To allow food prices to vary by region, and because most players quickly have enough gold that it makes no difference to them anyway, this feature scales up the base value of the cheapest food items using a square-root curve: V' = max(V, sqrt(V+1) * M) where V is the gold value and M is the minimum. With the default minimum of 3, this means food items worth 0 or 1 are scaled up to 3, while food items worth 9 or more are unchanged.

[b][color=yellow]Minimum Ingredient Price[/color][/b] - This feature works just like the Minimum Food Price above except that it applies to ingredients and the default minimum value is 7, because ultra-cheap ingredients pose an additional problem for [i]Trade Routes[/i]: some of them are part of the long trade loop, which means the Trade Supply feature will make (by default) 1000 gold worth of them available for sale from the appropriate merchant(s). If they were only worth 1 gold each that would require 1000 items to be available for sale, which would be absurd; this feature ensures that those items are worth enough that a mere few dozen will suffice. The formula is the same, so with the default minimum of 7, ingredients worth 0 or 1 are scaled up to 7 and ingredients worth 49 or more are unchanged.

[b][color=yellow]Ore Price Ratio[/color][/b] - This feature sets each ore's value to a consistent percentage of its corresponding ingot value (accounting for the input and yield quantities), so that smelting adds a consistent markup. This is mostly aimed at Dwemer scrap metal (which is severely undervalued in the base game), but it is applied to all smeltable items.

[b][color=yellow]Position Polling[/color][/b] - Because many exterior cells are not correctly tagged with their parent region location, [i]Trade Routes[/i] can't always use the most efficient method (cell change events) to detect when you cross the border from one hold to another. Every (by default) 5 seconds while you're outdoors in mainland Skyrim, this feature runs a quick check on your exterior worldspace coordinates to make sure [i]Trade Routes[/i] always applies the correct regional variations for your current location. The polling adds minimal script overhead and stops entirely when indoors or in another worldspace, but you can lengthen the polling interval or disable it entirely if you prefer.

[b][color=yellow]Speech Scaling[/color][/b] - This feature re-tunes the game's barter difficulty (sometimes called merchant difficulty), which is the rate at which your buying and selling prices improve as your Speech skill goes from 0 to 100; specifically, it overrides the fBarterMax and fBarterMin game settings. The values that [i]Trade Routes[/i] applies are carefully calibrated so that the long and short trade routes offer the intended profit margins at the intended levels of Speech skill, Haggling perks and enchanted bartering gear. This is also the mechanism by which [i]Trade Routes[/i] supports many popular mods that alter the effects of Haggling (and/or other Speech perks), since that would otherwise disrupt the intended tuning. By default, [i]Trade Routes[/i] will automatically detect the active perk mod and set fBarterMax/Min accordingly, but you can disable this override if you prefer to use the settings provided by another mod (though that may of course make it difficult or impossible to trade profitably).

[b][color=yellow]Quest Effects[/color][/b] - There are several possible game events (in the form of quests) which can influence the supply or demand of various items in various regions. For example when the player liberates a mine, then the miners will get back to work and the corresponding material will drop in price and rise in merchant supply. Conversely if the player causes some supplier to shut down, then those products will rise in price and drop in merchant supply. This feature is enabled by default, which will require the player to complete several quests in order to unlock all trade routes, but it can be disabled to make all trade routes available no matter the player's actions.

[b][color=yellow]Barter Warnings[/color][/b] - Since it can take several seconds for [i]Trade Routes[/i] to finish updating all item prices when you move from one region to another, there is a small window of opportunity to open a merchant's bartering menu in the middle of this process, causing prices to seem erratic. This feature will pop up a warning if that happens and advise the player to close the menu; when the update is complete, the player will then get an all-clear message to re-open the barter menu. In practice this almost never comes up since the update takes only a few seconds, so it's recommended to keep this enabled just in case.

[b][color=yellow]Notices[/color][/b] - [i]Trade Routes[/i] aims to be fairly unobtrusive by default, but you can use this feature to enable some routine messages if you'd like to keep tabs on when things are happening (such as a price update when you cross a hold border).

[b][color=yellow]Debugging[/color][/b] - This feature should only be needed if you're helping to track down a bug in the mod, or if you're especially curious about its inner workings.

The Special Functions are described in the main mod description.

[b][u][color=cyan]ADVANCED PRICE TUNING FEATURES AND OPTIONS[/color][/u][/b]

[i]Trade Routes[/i]' regional item pricing can be fine-tuned by activating the Price Tuning panel, which is hidden by default to avoid accidental spoilers.

[center][url=https://i.imgur.com/CLsByzw.png][img]https://i.imgur.com/9mta0LX.png[/img][/url][/center]

[b][color=yellow]Outer and Inner Markup[/color][/b] - [i]Trade Routes[/i] defines the price adjustments for the five price/supply levels using only these two ratios: the Outer Markup (1.4 by default) defines the ratio of Supply to Origin prices and the ratio of Destination to Demand prices, while the Inner Markup (1.8 by default) defines the ratio of Demand to Balanced prices and the ratio of Balanced to Supply prices. This ensures that the second-widest price differentials (Origin to Demand and Supply to Destination) will always be the same, since either one might create a short trade route.

[b][color=yellow]Speech Scaling[/color][/b] - This is the same feature that appeared on the main options panel, but more options are available here. In addition to the disabled and auto-detect settings, from this panel you can peek at any of the built-in presets for various Speech perk mods, or define your own custom fBarterMax/Min values.

[b][color=yellow]fBarterMax and fBarterMin[/color][/b] - These options display the values that [i]Trade Routes[/i] will apply, overriding the values set by any other mod (even ones that are below [u]TradeRoutes.esp[/u] in your load order). Changing the Speech Scaling option will update these values to the chosen preset, and changing the values will automatically select the "custom" Speech Scaling option.

[b][color=yellow]Multipliers and Price Anchor[/color][/b] - This table shows the effective result of your Outer Markup, Inner Markup and Price Anchor options. The level that is defined as the Price Anchor will always have the multiplier 1.0 (meaning items will have their unmodified vanilla values in regions where they are at that trade level), and the Outer and Inner Markups are applied outward from there. With default settings (as shown in the screenshot), the Price Anchor is Low which means the Bottom Multiplier (applied at items' Origin) is 1.0 / 1.4 = 0.714, the Middle Multiplier (Balanced) is 1.0 * 1.8 = 1.8, the High Multiplier (Demand) is 1.0 * 1.8 * 1.8 = 3.24, and the Top Multiplier (Destination) is 1.0 * 1.8 * 1.8 * 1.4 = 4.536. Clicking on any price level in this table will set the Price Anchor to that level and recalculate the multipliers accordingly.

The bottom half of this panel is a calculator for the profit potential of a long or short trade route, and the time efficiency of the short loop, given all the relevant settings: the detected Speech perk mod, the Outer and Inner Markups, the fBarterMax/Min settings, and the amount of fortify barter ("better prices") bonuses on the player (from potions, blessings or enchanted equipment; this can be set by clicking on the price bonus header). With default settings and no bonuses (as shown in the screenshot), we can see that no profit can be made at Speech skill 15, but at 20 (which implies two points in Haggling) the long routes will begin to yield a profit of ~126 gold while the short route is not yet profitable. With 40 skill (and 3x Haggling) the short routes turn a small profit, but they never become time efficient without at least a little specialized equipment; if you change the price bonus to +30% (which could be, for example, a Blessing of Zenithar and a good quality Necklace of Haggling) you should see the short loop become more efficient with 60 skill (and thus 4 Haggling perks).

[b][u][color=cyan]ADVANCED SUPPLY TUNING FEATURES AND OPTIONS[/color][/u][/b]

[i]Trade Routes[/i]' regional merchant supplies can be fine-tuned by activating the Supply Tuning panel, which is hidden by default to avoid accidental spoilers.

[center][url=https://i.imgur.com/jecNS99.png][img]https://i.imgur.com/Itod1jH.png[/img][/url][/center]

[b][color=yellow]Average Quantities[/color][/b] - These options control the average number of each individual item of a given type that would be available for sale in the regions where that item has the Balanced trade level. This serves as the baseline which is then modified by the corresponding Minimum Level setting and the Weight settings, described below.

[b][color=yellow]Average Imports[/color][/b] - This setting deserves special mention because it operates differently than all the other Average Quantity settings. While most established merchants' supplies are governed by item availability in their own region, there are a few traveling merchants in the game (the Khajiit caravans and the random encounter Peddlers) whose inventories are exactly the opposite. Because those merchants are specifically traveling around, they actually carry more of the items that are rarest in the region where you encounter them, and few or none of the items that are plentiful in that region (since the local merchants already stock those items). So the Average Imports setting controls these merchants' supply of any item that has the Balanced trade level wherever you meet them, but the Weights are applied in the other direction for those merchants: items at the Demand or Destination levels will receive the higher Weight multipliers, and vice versa.

[b][color=yellow]Weights[/color][/b] - These settings define how much more plentiful items get in their higher-supply regions (Supply and Origin), and how much scarcer in their lower-supply regions (Demand and Destination), if they're sold there at all (according to their Minimum Level). They are applied as ratios against the Middle Weight, so with default settings (as shown in the screenshot) items will be twice as plentiful in their Supply regions as in their Balanced regions, and so on.

[b][color=yellow]Minimum Levels[/color][/b] - These options define the minimum supply level at which items of a given type will be offered for sale at all -- you can think of it as a kind of "local-ness" setting. For example with default settings (as shown in the screenshot) food is fairly local, meaning any particular food item will only be sold in the 3-4 regions where its supply level is "high" or "top" (i.e. Supply or Origin), and can never be found for sale in any of the other 5+ regions. Gems and Soul Gems, on the other hand, are not very local; they will be found for sale in almost every region, except for the 1 or 2 which are their respective Destinations. Note that some item groups override this setting internally, so there are certain items that you may still see for sale in multiple regions even if you were to set every Minimum Level to "top".

[b][color=yellow]Previewed Item Type[/color][/b] - This option changes the item type whose effective average supply quantities are previewed in the table below it. As shown in the screenshot, Ores and Ingots have a quantity of 0 at the Middle, Low and Bottom supply levels because the Ore & Ingot Min Level is set to "high", so these items are only ever sold at their Top and High supply levels (their Origin and Supply regions). The average per-item quantity that is sold in those regions is derived from the Average Ore & Ingot value of 2.0 and the Weights: 2 * 6 / 3 = 4.0 for High, and 2 * 9 / 3 = 6.0 for Top.