do you buy used amps n pedals

Yes

I agree with Alex. If you look on their website, there is tons of used gear. Some of it is from trade ins, some of it is from purchase. You have to keep in mind that they are reselling, and they need to make a profit off of what they buy.

I'm a drummer and DJ so I dont know anything about it sorry

Yeah, the return is not usually great

Yes they do. Not all equipment though, gotta be in good working order, clean, and something they would be able to resell. Don't expect too much in return as they are a business and have to turn a profit