After asking about the refill vs swap dilemma several of you had some great suggestions about getting a new tank refilled including fire extinguisher places. In my case I have a pretty new CO2 tank and didn't want to swap for a pre-filled used tank. Some of you may have been able to buy a used one on the cheap - in which case the swap idea becomes much more desirable because of convenience. For me, I wanted to fill my new one.
Airgas on Tennessee Street here in Johnson City only does swap-outs. Holston Gases on Spratlin Park Drive in Gray will not fill anything less than 20 lbs. cylinders, and they work on a swap basis as well. Valley National Gases Inc. on Perma R road fills tanks on site (you have to leave it overnight) and are friendly. Just thought I'd share the info.