I went away from eq2 to WoW to try it for a while, I did and I absolutely got addicted to WoW because of the super wide variety and availability of custom user interfaces, really extreme ones as well with huge useability (didn't actually like the game very much, just my downloaded gadgets for it lol)!
However one of my favorites were this mod called "Auctioneer", what it did was search the whole auction house and copy the prices to it's database, (this was all done ingame by the push of a button on your auctioneer screen) it automatically browsed the auctioneer and captured the prices for all the items, duplicates and non duplicates.
Now bare with me, this might be confusing and I don't know if it is correct since I did not calculate and write the mod;
Let's say you see 23 adept books of the same kind, it adds up the price for all 23 of them, finds the average and undercuts by 10% or 15%, that way you know exactly what is a good price to sell the book for. After it's done calculating that it showed exactly what it calculated and thought was a recommended price for the item you were trying to sell. After you're done and close the broker window, you still have the recommended price in the mod's database in your Eq2 directory, so next time you loot/collect an item, it shows up in it's description how much it is worth selling it on the broker... GENIOUS! Also, keep in mind that this searches the WHOLE broker, not just one kind of item (if you do not want it to that is) so it catches and calculates out the median of all the objects it's seen, so you could loot anything and see what a recommended price would be on the broker (providing the mod saw it on the broker once)
It's a really great add-on for that game, and I miss it so much. And let's not forget how overpriced everything is in Everquest II, the playerbase NEEDS a mod like this with such an effed up economy we have in Eq2.
If I didn't make myself clear enough, if you have any questions, any suggestions, or if I am bad at explaining. Please respond!
Edit #1: Added some more information that I forgot to include