Coupons—those slivers of papers that offer price breaks on so many of the products we buy—seem ubiquitous. They fall out of Sunday newspapers like confetti. They stare at us on almost every page of magazines we peruse. They cover the wrappings and boxes, inside and outside, of foods and other products we buy. Postal workers stuff our mailboxes with them. And they line the shelves of grocery store aisles. Many families have organized banks of them.