South Park: The Stick of Truth - Junk Peddler Achievement

Achievement - Junk Peddler
Sell 300 junk items.

You will acquire junk all throughout the game from looting bags, drawers, and knocked out enemies. If you loot all throughout your playthrough, you can get this very early in the game. NOTE that this achievement will void the For The Hoarder achievement. I recommend earning For The Hoarder first, and then selling your junk after you finish the game