I put $1000 towards a car that i wanted to purchase. I can no longer afford it and the dealer wont give back my deposit

I signed no contract or no paperwork. All I received was a written receipt that said i gave them $1000 deposit towards the car. He claims that he turned down other offers and that I cant change my mind because I already told him i wanted the vehicle. Again i never signed anything I just gave the deposit and said i would try to come weekly to pay until the car was paid off