For example, say you have a 50¢ coupon for a national brand soup. The national brand is selling for $1.50 for a 10.5 ounce can. The store brand is selling for 80¢ for the same size can. If you used the coupon and bought the national brand it would cost you $1.00 or 20¢ more than buying the store brand. So in this case the store brand is still less expensive.