I was at a thrift store last week and asked the lady if they had any new watches lately (they have a basket with about 50 watches that I had went through previously--all $1). She said "not to many." Then she proceeded to tell me that some guy was in a few days before and bought a swatch watch and right after he paid for it he told her it was worth a lot of money. I thought to myself "dumba@@". Another story... An acquaintance that volunteers at a church TS was telling me that a lady bought a purse for a couple dollars and sold it online for over a thousand. She then went back to the TS and bragged about it and didn't give any kickback. Why do people do that? If you're going to tell them how much you made or are going to make off of them perhaps you should give some back??
I think the kickbacks depend on the situation. Like BK's mentioned sales I would've done the same. Goodwills, Savers etc. no! Just don't go back and brag.