Coupon clips

Why are so few stores doubling coupons? It's expensive. It's the supermarket that pays for such promotions, not the coupon manufacturers. As the economy has tightened, supermarkets have cut back on such promotions.

Why don't other stores accept expired coupons like Cub does? Retailers are not supposed to accept expired coupons, according to the coupon's terms of compliance. There is a time lag between the time of redemption and the time when the coupon gets to clearinghouses, which allows Cub to do it. Apparently, enforcement is not a high priority.

Why don't warehouse clubs such as Costco and Sam's Club accept coupons? Warehouse clubs often sell items in multipacks with bar codes that don't match up with single-item coupons. The packs often contain items that are "not for individual sale."