scammers

They pose as buyers, and agree to pay any price, even if it's much higher than any normal person would ever agree to. Then they send you a check, certified check, or cashier check. The amount they send may be several hundred higher than your agreed price. They claim this is so you can then wire that extra amount to their shipper, with payment being by some unorthodox means, like a wire transfer or gift cards. Only later do the victims realize the check they deposited into their account was fake and bounces. Of course the money they wired out was real, and went to the scammer or accomplice. This seems to be the most popular form of scam but certainly not the only one. Scammers will pose as sellers too, and demand you send them earnest money or prepay a fee to release a car from storage, often posing as US military members who can't do it themselves since they're "serving overseas." Regardless of the scam, never pay money via a wire, or by buying and sending gift cards or gift card codes. Insist on meeting buyers and sellers face to face, you can always pick a mutual safe ground like a police station lobby.