i'm slowly making the switch from walmart fabs to buying online. (like most people i'd prefer to see it before buying but in-person shopping anywhere else is inconvenient and pretty expensive unless i catch a sale.
the WalMart fat quarter bundles are made up from a variety of fabrics. some i've never seen on the shelves in our walmart. they're very similar in both look and feel to some i've seen for $4 - $8 per yard elsewhere. i found one, though, that included a cut from a fabric they sell themselves for only $2.50 per yard. you aren't necessarily getting a "steal" on the FQ bundles (8 per roll) but if you choose carefully you'll pay about the same you'd pay elsewhere if the fabs are on sale.
i'll probably pick up a few rolls if any are left the next time i go. they come in handy for small projects and will save me the gas i'd need to get to the nearest fabric store or the postage i'd pay from an online shop.