Can i get back my deposit from the dealer

Without a signed contract specifying, e.g., that this was a refundable deposit as long as you changed your mind within 3 hours, you have no protection. The dealer can argue that during that 3 hours, they turned down 6 offers for this car, because they were holding it for you. How long did you think they would hold the car for you based on your $500? Hours? Days? Weeks? You can try threatening them with Small Claims court, and if they don't give you your deposit back, take a shot, but I don't think you've got a very good chance.

The dealer is playing hardball with you. Make sure they know you are serious. Send a certified letter demanding the money back. If they don't pay up, sue them in small claims court. No guarantee you'll win, but if you give up, they win. The legal side of this boils down to what the actual agreement was. Did each of you mean it to be non-refundable? What is the industry practice? Did they lose business because the car was off the market? Because it's uncertain who'll win, be ready to negotiate once you've let them know you mean business.