Where to get dry ice or CO2?

[RetiredJedi]

My local grocery store sells dry ice, but I live in a fairly large urban area.

Places like Sports Authority and D i c k's Sporting Goods sell CO2 tanks...where to get them filled is a different matter altogether.

and once you get one bottle, I think you can go into Wal-mart and switch it out for a full one. The price obviously depends on the size of the refill.