I'm not saying this happens for every product Wal-mart carries, but because it does happen I will not shop there (among other reasons.) A school mate and one of my professors both told stories in class about comparing Walmart products to products that come directly ordered from the manufacturer. Professor said how Johnson and Johnson baby shampoo has different ingredients at walmart and a different SKU, the school mate told a story about how he and another employee took apart a gun from their shop and one purchased from Walmart and there were different parts in the same exact gun and also a different SKU. The SKU would be the same for the digits part and the last letter on the end was added especially for WalMart.i've never had issues at ours. even a 5 minute wait would beat going to the grocery store for pepsi & poptarts, oreilly's for valvoline oil, office depot for sharpies, home depot for ortho bug killer, and bass pro or some other hunting store for federal ammunition.
as long as you are getting consumables and not durable goods, you're good to go because its all the exact same name brand shit you find anywhere else, all in one place, and all cheaper.
Walmart is lower quality and has 2% of our GDP in America. That sounds like something I don't want to get behind.