If you ever get to see it, there's a big expose on Walmart where they follow around some of the higher up people, it's sad.
Basically they have these scouts that go out and find failing or slower moving towns and put in a Supercenter. They offer prices that are just MIND BLOWINGLY low until all the other small businesses go out of business since they just cant compete.
After that, they raise their prices back up if not higher than what the smaller places sold them at before they went out of business.