Here we will describe some of the Price Sources referenced on the What is a Price Source? page in more detail.

Price Sources will return a numerical quantity in gold/silver/copper, and can be split between external and internal sources. External sources are provided by and/or calculated by TradeSkillMaster, such as DBMarket or DBRegionSaleAvg from AuctionDB, and internal sources are derived or calculated from other configurations and activity you have set or recorded in the addon, such as crafting or avgbuy.
 

avgBuy (Avg Buy Price)
avgSell (Avg Sell Price)
maxBuy (Max Buy Price)
maxSell (Max Sell Price)
minBuy (Min Buy Price)
minSell (Min Sell Price)
SmartAvgBuy (Smart Avg Buy Price)

From TSM Accounting, avgBuy and avgSell will return the average price for all purchases and sales for a particular item, respectively. In TSM 4.10, the 'Smart Averages' option has been retired in favour of a new Price Source you can reference separately and independently: SmartAvgBuy - This will return your average purchase price across your last X purchases of the item, where X is the quantity of the item you currently possess. If you do not possess the item then SmartAvgBuy will be invalid.
minBuy and maxBuy are the minimum and maximum price you've purchased an item for in your Accounting data. Conversely, minSell and maxSell are the minimum and maximum price you've sold an item for in your Accounting data.

Crafting (Crafting Cost)
matPrice (Crafting Material Cost)

From the TSM Crafting module, the Crafting cost of an item is the sum of the material prices (matPrice) of each individual item used to craft the recipe. You can change how matPrice is calculated by default in your Crafting options under 'Default Price Settings', you can also change the individual matPrice for items in the Materials tab of your Crafting page. An item can only have a matPrice if you have a recipe that uses the item as a material. You can not reference the Crafting cost of an item if you do not have the recipe.

Destroy (Destroy Value)
vendorBuy (Buy from Vendor)
vendorSell (Sell to Vendor)

A particular items Destroy value is the value of the items you would receive by destroying it, on average. Destroying an item can be done by milling, prospecting or disenchanting it. By default, the Destroy value is calculated with the DBMarket values of the items you would receive, you can change this in your Tooltip Options.

vendorSell is the value of a particular item when you sell it to a vendor. vendorBuy is the cost of a particular item you can purchase from a vendor. Note that vendorBuy is only populated for a particular item when you visit a vendor that can sell it.

Introduced in TSM 4.10, these Value Sources are generated by the Operations applied to your Groups. From the first Auctioning Operation assigned to your group, AuctioningOpMax, AuctioningOpMin, and AuctioningOpNormal will return a numerical quantity in gold of the Maximum, Minimum, and Normal post price, respectively. Similarly, ShoppingOpMax and SniperOpMax will return a gold numerical quantity of the Maximum Shopping Price and the Maximum Sniper Price from the Shopping and Sniper operation, respectively, assigned to your group.

TSM AuctionDB has several sources that offer item values in reference to your specific realm and your region.

DBMinBuyout (AuctionDB - Minimum Buyout)
DBMarket (AuctionDB - Market Value)
DBHistorical (AuctionDB - Historical Price)

DBMinBuyout is the lowest priced auction on your realms Auction House, as of the last pricing update processed from Blizzard's Auction House API. This value is not 'real-time', your pricing data may be 30 minutes or older before the next pricing update. If an auction is posted between pricing updates, this value does not get updated with the new lowest priced auction until the next pricing update. If there are no auctions for a particular item on your realms Auction House, DBMinBuyout could be an invalid price source.

DBMarket is a weighted 14-day average of the auctions listed for a particular item on your realms Auction House, favoring the most recent 3 days of pricing data. It is explained in much more detail on the AuctionDB Market Value page. Note this value does not indicate what an item will sell for, only what the item is currently being listed for on your realms Auction House.

DBHistorical is a 60 day average of the DBMarket value for a particular item on your realms Auction House.
 

DBRegionMarketAvg (AuctionDB - Region Market Value Average)
DBRegionHistorical (AuctionDB - Region Historical Price)
DBRegionSaleAvg (AuctionDB - Region Sale Average)

DBRegionMarketAvg is the average of DBMarket across all the realms in your region for a particular item.

DBRegionHistorical is a 60 day average of DBRegionMarketAvg for a particular item in your region.

DBRegionSaleAvg is the average sale and purchase price for a particular item in your region. This data is collected from TSM Accounting data via the TSM Desktop Application.

Note: DBRegionMinBuyoutAvg has been retired.