Exchanged my tanks yesterday. Cost $126.64. There are very few places in my area that sell gas. It's been a while since I've exchanged but I'm positive there were far more places a decade or so back. The guy at the shop seemed almost apologetic, and asked me "is this okay" (regarding the price). What to do? Go somewhere else and most likely pay just as much? I was charged $22.50 for "hydrotest fee" for the O2 bottle and $27 for "requalification on acetylene" bottle. The O2 is (I think) 80 CF, along with some reference to Refill 2.2 (5.1). Not a large tank. The Acetylene is (I think) a 2A tank, which I can't find much of any info on. Most likely an old outdated standard size. There is some mention of 2.1 on the bill but I don't know what this means. At any rate, NOT CHEAP!