Shelf coupons, those little tear-off pads or blinking machines you find in the grocery aisle, seem like a great way to get an instant discount. However, these coupons are often loaded with very specific and confusing fine print. These hidden rules can easily invalidate the coupon if you are not paying extremely close attention. This can lead to a frustrating surprise at the checkout. Here are thirteen common fine print rules that can trip you up.
