Walmart Price Matches

I live in a very small town. About 4 years ago we got a Walmart Supercenter and ever since then I have bought everything at Walmart. They are always cheaper right?
Over the last several months I have been on a mission to drastically reduce our grocery spending. After taking the Supermarket Savings 101 course from Biblical Womanhood, I decided to start shopping according to what was on sale, and to shop at different stores. The sale paper came out for one of our local grocery stores and they had some really good deals. I was very excited and went to the store all by myself (no kids.) When I got there, they were out of every single item in their sale paper that I was interested in buying. Very discouraged I left the store without buying a thing. After sharing my story with a friend, she told me that happens quite often and so she just takes the sale paper to the Walmart checkout with her because they price match competitors ads. Am I the only person in the world who didn't know this? On Friday after the post office and the bank, we went to Walmart and they had all of the items I was looking for. I put the price match items in the front of the checkout and let the cashier know I had several price match items. It was that easy!