Is the contract valid, and is the buyer entitled to return the car and charge the seller for the expenses, considering that the seller disregarded the car's true market price, which is seven thousand Riyals less than the agreed-upon price, and refused to lower the requested amount?

If the price is not known before or during the contract, the sale is invalid due to ignorance of the price, as knowledge of both the price and the commodity is a condition for the validity of the sale. However, if the price is known during the contract and the buyer agrees to it, the sale is valid, and she has the option [to revoke the contract] if it becomes clear that she was defrauded in the price. As for the costs of returning the commodity in the event of rescission of the sale, they are borne by the buyer.