yeah i would stay away from walmart's boxes
i dont think they're made out of MDF. their probly not braced(so their weak) and they probly leak air(lack of depth and SpL). he'd be better off gettin a decent prefabbed box made out of MDF for about $40 shipped off ebay.
but Wal-Mart does have what seems to be a decent deal right now. they got 2 5" LCD's and a dvd player for $275. but that may just be at the wal-mart here tho. i dont think the brand is any good but im not a big video enthusiast... i would like to have some screens tho