The supermarket may advertise another $1 discount on every $15 worth of dog food. The customer can redeem both the coupons and pay only $13 for the dog food and thus save $ 2 on every visit. This may not sound as much of a savings but it all adds up. Buying items close to expiry date have a series of attractive discount coupons attached to them including dog food coupons. Such sales are beneficial for the supermarkets as well as the customers