Sounds like a scam, I say: ask your LHBS.
On an off chance, I asked my LHBS and they gave me an address of a welding gas / refill station here in Vegas that “doesn’t exist” in the phone book or online (gaagle doesn’t even know they exits)... but they DO!
$15 for a 5lb co2 refill and $17 for 80cf of nitrogen, after taxes, hazmat charge, etc. Usually it’s not the size of the tank (5lb or 20lb, maybe a couple of dollars more). They fill onsite, though I’ve never gotten 1200 psi; more like 800-900 psi. The fill usually takes about 2 minutes and the tank comes back heavier and freezing cold.
In Vegas, Airgas will only exchange for like $25 and local fire extinguisher place charges $35 for a 5lb fill.
I can push about 6-8 5gal kegs plus use some for cleaning lines on a 5lb before a refill.
