You can get it refilled at a liquor store or a welding supply, amazingly enough. I go to Two Bucks Liquor, but when I asked them where they get their CO2, they said a welding supply company that was even closer to my house! :roll:
Liquor store has to be good enough for human consumption as people use it in their kegs, I dont think there is really that much difference, although I am sure there is some