When the ownership of the third party on the object of sale is determined, two duties are created for the seller. "Price refund" and "payment of compensation" to the customer who was not aware of the void of the transaction. In the payment of compensation, various judgments were issued by the courts; So that it caused the issuance of the judgment of uniform judicial precedent 733. This judgment considered the reduction in the price as compensation and although in some cases it was a solution to the problem, but the differences of opinion of the courts in the method of compensation still remained. Finally, the uniform judicial precedent 811 announced "the amount of price increase (inflation) of properties that are similar to object of sale" as the basis for calculating damages. But the question is whether the decrease in the value of the price is included in the concept of "compensation" in Article 391 of the Civil Code? And is the compensation due to the decrease in the value of the price based on civil liability? What is the legal advantage of compensation method of the uniform judicial precedent 811 over other methods? In this research, the answer to those questions has been given by descriptive and analytical method; And the price when it is money has been separated from the price when it is a definite property,