Laura promises to pay Stuart "a reasonable amount" for repairing her car.Stuart sends Laura a $500 invoice and Laura sends Stuart a $350 check marked "payment in full." There is an agreement created by promissory estoppel.

While promissory estoppel may create a legal obligation based on a promise, in this case there is no clear promise made by Laura to pay a "reasonable amount" and no reliance by Stuart on such a promise. Furthermore, Laura's check marked "payment in full" creates a legal concept known as accord and satisfaction, which means that Stuart has accepted the $350 payment as full and final settlement of the debt.