I asked my local pharmacy if their oxygen supplier sold argon co2. They had large tanks that I would have to lease and refill but a small tank they would loan me free and fill or swap for $20. I got the small one but don't know how long it will last but was happy to get it close to home and the welding sure is nicer with the gas. I don't know what units the tanks are but when I was looking the sizes were 20 40 & 80. The tank I got was the 20 size.
