when walmart located in a smaller town, often the local retailers hardware, clothing and appliance are unable to successfully compete and are driver

when walmart located in a smaller town, often the local retailers hardware, clothing and appliance are unable to successfully compete and are driver out of business why does walmart have a cost advantage over its competitor and charge lower prices? If Wal-mart drove its competitors out of business, and behave like an unregulated monopoly, what would happen to its prices and why?