I tried those places too Harvey, and nope they wouldn't sell me a cylinder. Rent yes sell no.
Ok tell you what I feel like I'm flogging a dead horse here. No wants to believe me, fine. Go ahead and call all those places and try to buy a CO2 cylinder. Post back what you find out. I'll say it one last time, I think the best deals will be MO. But hey don't take my word for it, obviously my experiences don't count for anything.
I'll go so far as to provide you with numbers. Please, call them, ask to *buy* a CO2 cylinder.
Praxair - 236-6511
Liquid Air - 777-4700
Medigas - 236-2166
Oxypro - 279-5055
BOC - 279-7581
Sprouse Fire - 265-3891
There are a host of others too, but that should get you started.
And, let's assume I've been wrong all along. Let's say you do find, say, a 10lb cylinder somewhere that they will sell you. Please post this info and the price.
Just remember, there's a 10lb cylinder sitting at OA for $100.
https://www.oceanaquatics.com/index.php?cat_id=39
Knock yerself out.
PS. FWIW, I use Sprouse for refilling my cylinders, and have also had them do two hydrostat tests too. I'm pretty happy with their service. I think I once also had Oxypro fill up my little cylinder, and they were good too, but their hours are a little less convenient for me (close at 4:00 or 4:30 IIRC).