The wife overheard a couple of people at her work talking about a feature on the Walmart app called 'Savings Catcher' and after checking it out, it's pretty damn cool. I stop at Walmart quite regularly for groceries just because it's convenient and they have pretty decent prices. But, this makes it even better. You will need the Walmart app on your smart phone for this though.
Go shopping at Walmart, when you are done, open the Walmart app and go to the Savings Catcher section. Scan the barcode on your receipt and Walmart will scan sales/advertised prices at stores in a 50 mile radius of you. If they find a lower price, they will credit you the difference. So far, 2 out of the 3 receipts I have scanned and have been processed have found better deals for me and have given me a credit to use at Walmart. Now, to use the credit, you will have to use their 'Walmart Pay' feature which is like Apple Pay or Samsung Pay or Android Pay and all those apps of the same type. But to save money, that will make it worth using their app at Walmart (at least for me).