Monsoon, the companies I have dealt with generally exchange cilinders, if You want the one You own back You have to wait FOREVER, as they don't fill them on site. When You turn in Your customer owned tank, You may get back one with their name on the collar. AND they have become a PITA about which tanks they will fill and which ones they won't. Allso, no trading for a different size. They don't want to sell any decent size cilinders as customer owned. By the way I am refering to Airgas, who aquired BOC's retail businiss, and is now the only game in My town. Do I sound happy or what? Still, I don't want to rent a bunch of tanks.
Where did you find that deal at? I was quoted $250 each on tanks. This is a small acetelyne and a 122CF oxygen. Also, there are three different gas suppliers in town so I have found one that will fill customer owned cylinders on site. For the tanks I listed above the oxygen was quoted at $16 to fill and the acetylene would be between $25-39 depending on the temperature and the amount it would hold that day. To lease any size is $50 each cylinder per year or $165 each for a 5 year contract which would save about $150.