According to the price, the contract can be divided into open contract and closed contract  The opening price refers to the price that can only be determined through calculation according to a certain pricing method, and the closed price refers to the price that has been determined at the time of the conclusion of the contract
A sale contract without a fixed price is an open contract
Mr. Li signed a contract with the decoration company, agreeing that the total price for decoration is 120000. When checking out, the decoration company proposed that Mr. Li asked to use higher standard hardware in the decoration process, so he asked Mr. Li to pay an extra 2000 yuan.