Question 1: Economists define costs in terms of opportunities forgone. What opportunities are forgone by Wal-Mart's "everyday low price" marketing strategy? Who pays the costs of Wal-Mart's low prices?
Question 2: Wal-Mart's wages are above the legally required minimum wage, and health benefits are not legally mandated. Are there reasons for a business to take actions not required by law but which might reduce profits?