Walmart's promise to shoppers is simple: everyday low prices. To pull that off, it built a supply chain designed around one goal, keeping costs down at every step. Walmart buys in enormous volume. Ordering millions of units gives it the bargaining power to push suppliers for the lowest possible price per item. It also runs its own network of distribution centers and trucks, moving goods from suppliers to stores cheaply and on a tight schedule. As Walmart grew, it scaled up: building bigger, more efficient distribution centers and adding stores, aiming to grow sales faster than costs rise. Lower costs let Walmart charge lower prices than many rivals and still make a profit. A company chasing low prices builds a different supply chain than one chasing the highest quality.