" But how do we know the value of our finished goods?” she asks. “First of all, the market determines the value of the product,” says Lou. “And in order for the corporation to make money, the value of the product—and the price we’re charging—has to be greater than the combination of the investment in inventory and the total operational expense per unit of what we sell. "

― Eliyahu M. Goldratt , The Goal: A Process of Ongoing Improvement