回复：请大家帮帮忙，看看这买车押金还能要回来吗？

A court will follow doctrine of caveat emptor, buyer be aware, that you should do inspection yourself to make nothing wrong with the car before you buy. Unless you have proof that they misrepresented some material facts, you will probably lose because you signed a contract and you breached it by withdrawal from the deal. They can sue you in the contract but their damage will be limited to contract price minus market price. They must act in good faith to resell the car and claim the difference. Let's say if they sold it to another for $8000, then you are responsible for the $300 difference. You will also be liable for the $300 reliance damage because they relied on your promise to buy, to their detriments. They should not be awarded a total value of $8300. If they could not resell, a court must find the reasonable market value for the car and force you to be liable for the difference, plus reliance damage. Be aware that if this is between you and a dealer, you must pay for the full vlaue of the car because a dealer can claim lost volume sale.

They could also sue you off the contract under promissory estoppel because they relied on your promise to buy.

Either way, your $500 should be treated as a deduction to the damage and if the damage is less you may get some back.