Oh, that stinks, iTore. I work at a bank, and it depends on bank policy, but also for auditing reasons, our bank doesn't typically deposit checks into an account if their name isn't on that account. Now, if your bank knows you, they may accept it if you let them know you sold something and they got your name wrong. Hopefully the check is good...do you have contact information from them if the check doesn't clear? Does the check have an address/phone number underneath their name in the upper lefthand corner? See who the check is drawn off of (what bank it is through). If there's that bank in your town, you can go to that town, they can look up the account number and they can typically tell you if it will clear or not. Some banks charge you if you deposit a check and it gets returned, so that'd be one way of making sure and avoiding that fee.
Sorry to ramble on, just some ideas that could maybe help you out.
Edited to add: Try not to feel like an idiot. I know it's hard not to when you've possibly made a mistake. This coming from someone who was scammed out of $600 my freshman year of college. It was terrible. I beat myself up for a while. Some for good reason, some for not. People who con you are typically good at what they do.