Quantum valebat

QUANTUM VALEBAT, pleading. As much as it was worth. When goods are sold, without specifying any price, the law implies a promise from the buyer to the seller that he will pay him for them as much as they were worth.
     2. The plaintiff may, in such case, suggest in this declaration that the defendant promised to pay him as much as the said goods were worth, and then aver that they were worth so much, which the defendant has refused to pay. Vide the authorities cited under the article Quantum meruit.