Walmart does have cheaper prices on DVDs and CDs, some OTC meds, some groceries (and will price match any printed ad), etc. Shopping judiciously at stores including 5 grocery stores, Sams, Walmart, Kmart and 3 thrift stores helps balance the budget.
Our vitamins and supplements are definitely cheaper at Sams. $5.00 for 730 Bayer 81 mg aspirins and about the same price for 400 generic Zyrtec really makes a difference when you use 3 of each a day.
I'm investigating buying some survival type foods from Sams. Seems to be a whole lot cheaper than fresh for the dehydrated veggies.