Wal-Mart employs approximately 1% of the entire U.S workforce.
Their prices are low because they pay their employees as low as they can, and provide no benefits. Most employees are given pamphlets on how to apply for state subsidized health care (not a problem in most countries outside the U.S, however).
When a Wal-Mart is built, it kills most other local businesses such as grocery stores, car parts, mechanics, department stores, clothing stores , and electronic stores, many of which have been passed down from generation to generation.
It is a self-perpetuating cancer that reinforces the unsustainable model we choose to live by.
I go there MAYBE once a year but I feel sick every time I buy something from there.