I appreciate the responses, I went ahead and leased a 150cuft S size oxygen cylinder from Praxair for a year.
The lease costs $66 a year and the refill is $52, I live in Ontario, Canada and judging from some of the prices around here this is what's going to suit me best, I can also carry the tank pretty easily
The guy at praxair said I can upgrade my tank size to a 330cuft T size if I needed a larger capacity and told me they would keep the rental charges the same which is nice, the refill on the 330 is $100.13.
Once I get my work space set up for the tanks I'll be picking up an acetylene cylinder to go along with it then start ordering the metal for the frame.
Thanks