Can you sell something if someone else has already made a deposit?

Someone gave me $ on a deposit for some material I am selling, said they would pick it up in a week. I wrote down and signed that I had recieved their deposit. Then I get a call from someone who is willing to pay more. Can I sell it to them and return the other deposit, or is that illegal.|||No. Your accepting the deposit and signing the agreement is a contract.|||money grubber...dishonesty will always comer back on you.....|||Hey maybe you will get lucky and they wont pick it up and you can sell it for more to ! I think once you signed that paper you have to sell it to them . Even a verbal contract sometimes will is binding . I know how you feel though its like murphys law someone offers you more after you got deposit it sucks .|||IT'S IMMORAL AND UNETHICAL. BUT IF YOU'RE A LIBERAL THAT'S RIGHT UP YOUR ALLEY.