One of my family members introduced me to it the last time we visited New England and we saved a bunch of money on items we were probably going to buy anyways. All I had to do was bring up the app, type in the store name, and show the cashier the code/coupon on my phone and viola! Discounts!
Not Coupon Sherpa, but GeoQpons and The Coupons app - have pulled up coupons at Office Depot, Sports Authority, etc. Very handy to have. Freaks out other people in line as well.
We saved on a diverse plethora of things. Restaurants, baby clothes, and big retail stores. There were many options for buy X get X free/get X so many % off or simply a percentage off of a purchase. I'm sure we barely scratched the surface as we only looked up discounts at stores we went into and wanted to buy items in.
The app was free so it only cost us a little battery power and a few seconds to search for the store name each time.