Costco is famous for turning the experience of warehouse shopping into an adventure. Costco, one of the nation’s top three retailers and the world’s largest membership warehouse chain, has thrived by turning convention on its head. The company never advertises, charges its 64 million members to shop there and doesn’t mark up any product more than 15 percent. It’s a business model that works, generating $93 billion in annual sales. Correspondent Carl Quintanilla shows how Costco has grown to 600 stores, attracting loyal and affluent customers. They return repeatedly for the treasure-hunt thrill of constantly changing inventory, including diamond rings, steaks, wedding dresses and caskets. This CNBC Original documentary also explores a “Costco Effect,” the routine tendency of its members to succumb to the store’s discount-chic lure and spend more than they expect, often buying more than they need.