have you tried a panintball CO2 tank? there about 60 bux for 20lb

I realize I'm a little too late but if somebody else is looking for local used tanks I came across some at The Recharge Centre near the Blackfoot Inn. 10lb aluminum for a fair price and 20lb steel for much less. A very helpful bunch working there and quick co2 refill.

Im still looking for a good deal, if you could PM me the price they have that would be great.

FWIW I stopped by Oxypro this morning to fill my smaller cylinder. Since it's a 2.5 lb'er and it costs about the same to fill as my 20 lb'er, I got to thinking I should ask if I could buy a bigger cylinder since this smaller one is cute and all but it's hardly cost-effective to fill it. (A fill costs almost as much as what I paid for the cylinder itself!)

From Oxypro a 5lb cylinder would cost $160 and a 20lb cylinder would cost $300. (Yikes)

So this Recharge Centre (#5, 5622 Burleigh Cres SE; 258-1141) seems like a pretty good lead. I called them and although they don't have any cylinders in "right this second" they said they sell them 10lb, 15lb, and 20lb cylinders (both steel and aluminium) for anywhere from $90 to $120.