It's the app that allows you to scan your receipt and then Walmart looks for the items you bought in other store's sales papers in your area...if Walmart finds the item cheaper somewhere else, you get a gift card for the difference.
I just tried it today for the first time. I submitted my receipt and it said that they will let me know within 3 days if any cheaper items were found. You can do receipts up to 7 days old. I think I will like it :)