B.K.
To have a business account you have to have a tax-id number from the state. My business has one, and every year when we renew I have to fax or bring them a copy of the state tax-id form. So I'm not sure if you can get a business account without that. It enables us to purchase things without paying the tax, since the items are for resale. We also get the better hours. Other than that I don't think there are extra benefits.
As for the poster who says Wal-Mart won't do anything for you because they're in business for themselves.... I think that's what owning and running a business is mostly about. Making a good profit so you can live your life comfortably and hire others to benefit as well. (That's what my business is about, but on a much smaller scale.) Costco does the same thing actually. And I have a business membership there as well but the hours and prices aren't as good as Sam's -- so they're really doing NOTHING for me, whereas Sam's is. :-)