Coupon Sherpa. It's awesome because once you download it, you can find coupons for retail stores in the area you are located. It is also helpful because you're not standing in line to check out wondering if there is a coupon you could be using. If a coupon exists for a particular store, it is probably on Coupon Sherpa. A few weeks ago, I was just about to check out at Express. I whipped out my phone at the last second and found out I could save $30 off of my purchase. Sweet! You don't have to print the coupons out. Just show the cashier your phone with the coupon on it. One other thing you need to know is the coupons are not for grocery stores, but they have hundreds of other stores on there, depending on where you are located.
Hope you enjoy your new coupon companion!