Costco's bulk items are good quality...
Sam's Club sells cheap crap in bulk.
I've never been to a Costco, but go to my local Sam's often and the stuff they sell there is mostly name brand stuff in bulk. They have a private label and in most cases, it is as good as the named brand stuff. And you can beat there prices on meat.
That's precisely why I purchase meat elsewhere.
Wal-Mart buys their meat in bulk from Tyson. I have a friend who works there as an electrician and he brought it up. I've never shopped at Wal-Mart's meat department, though. There's a really cool super-mercado here that sells the same stuff for half the price, and it's the only place in town where I can find football-sized malangas and fresh lemongrass.
Offtopic, I know, but take a malanga to your local deli and have them slice it into thin chips and fry it up. Lays can't even touch that, although Terra chips are pretty damn good.