stereofidelic89,
I believe that both Walmart and COSTCO both have to order VSL#3 DS for you. But you'll need a doctor's script for it, and then they'll order it and call you when it comes in (and when you pick it up it should have been refrigerated, if it's NOT, then don't take it because it means it's been compromised).
As far as regular VSL#3, you'll have to call your local COSTCO and have them order it for you as well. But why not get the VSL#3 DS, unless your insurance won't cover it?