Case: The plaintiff (=pl) bought a car from the defendant (=def) for 50,000 shekels. Three years later he sold the car to a third person, who made the sale conditional on the truth of the claim that the car had been owned only by private individuals, not businesses (which lowers the price 10-15%), as def had told pl. Later, the buyer ascertained that the car had been owned by a business, and he forced pl to return 3,000 shekels to him. Def now admits that the car had been owned by a business, and pl demands to be compensated the 3,000 shekels he paid.

Ruling: Pl cannot demand compensation for the fact that def is responsible for pl’s having to return 3,000 shekels to his buyer. That is not direct enough damage and is actually not damage at all since the correct price for pl to have sold it is minus the 3,000 shekel. Rather the question is whether pl can demand back for what he overpaid.
At first glance, pl’s claim of overpricing is invalid, as overpricing by less than a sixth of the price is not claimable, as it is a forgivable inaccuracy (Shulchan Aruch, Choshen Mishpat 227:2). However this case differs from the classic case of mispricing, which involves the incorrect appraisal of a known entity, whereas our case involves misrepresentation of the sales object. A concealed flaw in the object is grounds to nullify the sale (see Shulchan Aruch, CM 232:3) if it is common for society to view it as a sufficient deficiency to justify such a determination (ibid.:6). Not only is it unclear that our case meets that criterion, but pl is not interested in nullifying the sale.
However, there is precedent for demanding a price reduction. The Rama (CM 233:1) says that if a buyer receives a lower quality meat than he ordered, he can demand return of the price differential. The source is the Terumat Hadeshen, based on his understanding of a gemara (Beitza 7a) that if one asked for fertilized eggs and received eggs that were unfertilized, even if he did not plan to raise chicks, he can demand a discount. The Veshav Hakohen (64) infers from the Terumat Hadeshen that one is entitled to the reduction even if the price difference is less than a sixth. The logic appears to be based on the principle in Kiddushin 42b that the laws of mispricing apply even to small inaccuracies regarding factual matters of weight, size, and number. As Rashi explains, such mistakes do not lend themselves to forgiving the inaccuracy.
Although the Ran learns the gemara in Beitza differently, it can be illustrated that he agrees that if there are grounds for nullifying the sale but it is not desired by the sides or not feasible, the price difference should be compensated. A similar case is discussed by the Radvaz (I, 324), where partners cut their fabric to divide among them and some of the fabric that one side received was blemished. He says that the other partner must compensate monetarily, as it is not possible to cut the fabric again. Therefore, def should compensate pl for the difference of the car’s value based on its previous ownership.