why are unid torches cheaper (15-20 fg per)
vs
3x3 key sets (30-35fg per set)

This is the way

Unid torches and keysets are much cheaper than that in d2...unless you are mistakenly posting about d2r in the d2 section........

Lol

My best guess would be that unid torches are collected with bots.

Keysets for sale generally come from manual grinding aka legit mfing

but the keys would still have to be used with the bots so..

Also I never buy unid items. There is a glitch that let's you iden items then if you drop the game your items are unid again when you rejoin a game. So the sellers are selling as unid but in reality they know what the stats are if they can proc that glitch.