Walmart has a new program called Savings Catcher! You can use it through the web, or you may use their integrated iPhone or Android apps. You just set up an account and scan in your Walmart receipts. Then, Walmart reviews other advertised offers and will adjust your prices to any lower prices found! If you used a coupon for an item, they will still adjust the price to the lower price!
If you set up your profile to receive texts, it can be even easier where it will automatically submit, based on your entering your phone number when you check out.
Their phone application offer even more useful features. One of them is that in some locations, you are able to SCAN the items as you shop, then when you get to the register, you can check out by synching up at the register.
In addition to the price matching, they also offer a DOUBLE your adjustment value if you redeem your cash back by using their Blue Bird prepaid account services.
I have been averaging around $1.25 back per receipt.
This and more can be found at: https://savingscatcher.walmart.com/