What size tank to folks have, how long on average does it last, and where did you get it? Looking at mixed MiG gas at the moment, might consider a small oxy/acet setup as well down the line (have torches, no tanks).
Tsc store is where I get mine.
They will sell you the tank then it's just an exchange process when it's empty.
Tsc also does sales on them often.
As for the gas, argon/ Co mix for steel with a mig.
I usually get a year or so on my tank. Hopefully 2 on This one since as I haven't done as much welding
You get a welder?
Your still welcome to borrow mine