Talk:The Vampire's Revenge/@comment-5965245-20180321134504/@comment-3234315-20180427225237

The item value on most articles is a hidden *.itm file value, that's used for calculating merchant prices – both, sell and buy. (I say "most", because at one point a different handling was intended that included game mechanics of this calculation and would have given a sell and a buy value. But this is deprecated, and only appears in some rare infoboxes on long-not-touched articles.)

But not only your reputation and charisma play a role in this calculation, also the – again: hidden – values of a *.sto (store) file's sell and buy markup, and for non-unique items the store's depreciation rate, which leads to lower buying prices the more items of the same type the merchant already has in their inventory. So much for your observed discrepancies … 😉