I called my LWS this morning to compare what I am paying for my rental oxy/acet tanks against purchase and I have a few interesting observations:
I currently rent a 282cf oxygen and a 130-180cf (med) acet tank that I use for OA welding and cutting. I pay $62/year for each tank.
Arcet doesn't sell tanks over 80cf oxygen, 55cf acetylene which rules out buying tanks from them for cutting anything thicker than foil - have to stick to their lease to get the big ones
Northern Tool/Gas Pony sells tanks similar to what I have
125cf Oxygen $289
145cf Acet $349
This means that I would recover my cost in 5 years if I bought the Gas Pony tanks, seems like a long time to me and I would have a smaller Oxygen tank.
Refill costs are about the same, I can refill the big Arcet rentals for $35 oxygen, $74 acet. Same price to refill the smaller Gas Pony tanks through Northern Tool.
The bottom line - the rental tanks from Arcet make more sense for me.