if someting at a yard sale is far more valuable than the posted price do i have to let the seller know? something at a yard sale is far more valuable than the posted price, do l have to let know? pieces in worse piece of furniture you've been searching for is marked $25. You know that similar condition have sold for more than 10 times as much. You're under no obligation to correct the seller her underpricing. One of the beauties of yard sales is such finds. Savor yours