Overpaying the Seller
When selling something, you open yourself up to spam messages and calls. A current scam will offer to send a check for more money than your asking price. The catch is the buyer wants you to use a portion of the money sent to pay the delivery person.
This should be a red flag for you. While the funds might be real, this could be a scam to “clean” money, and you (the seller) being the money mule in that scheme.