Well about a year or so ago I wanted to buy a 75/25 tank outright. I called the welding supply store and they said there was a shortage of tanks and they were not selling any. At that point I dropped the subject as I damn sure am not going to lease any tanks. Back in early August I was watching a local online farm consignment auction here. They had some "K" size oxygen cylinders on it. The first one went for what i thought was cheap money so I got an idea. Since this was a Friday auction and the welding supply store was open I gave them a call. I just wondered if they oxygen cylinders could be be swapped out for 75/25. The woman said heck yes steel is steel. We will exchange them. Well I bought some later on the sale.
Well it turns out they can only swap them for a "S" size in 75/25. That is a bit of a kick in the shorts as the K tanks are 240 cu ft and the S tanks are 120 cu ft. Of course 120 is plenty but I hate to trade down. One company is back to selling tanks and they quoted me $545 out the door. Of course to exchange these I have to pay the hydro test as they are old. It ranges $25-$50 and fills ranges $70-100. Now I have not got a sold quote from the shop I like the best. I have a feeling he can get me fixed up cheaper.
I picked up an oxy/acetylene tank set for free at an estate sale a few years ago, oxy tank was a K size and out of date. Talked to 'my guy' at the local welding supply about converting to argon and he was amenable to it, took a while but only cost me around $80 for test, new valve and fill.
For some reason no one wants anything to do with the big acetylene tank though, not that I really need it...
Around here most companies won't sell you anything over an 80cf, though I've heard some will do 120's.
Never get a straight answer as to why, just cuz...
Earlier this year I ran across a nice deal on an idealarc sp-200 mig, big beast for what it is but for $400 came with two partway filled 120's, one 75/25 and the other straight argon. Also came with a nice spoolgun, regulator, tips, helmets, etc in addition to a pile of unrelated misc stuff, tools/tooling.
I'm due to fill the 120 argon so I'll soon find out what the $'s are these days, goes up a bit every time it seems.
Have a 60 with 75/25 and an 80 argon and just fill them myself off the 120 and/or K tank as the bigger tanks have always been a much better deal to fill.