I bought a bulk co2 tank(25lb capacity)$110.00 with siphon tube installed another $10.00,and my first fill was free.cost me $22.00 for a fill.I built my own fill station from home depot parts,teflon tape,and 2 feet of steel braided
remote hose.I use a digital fish scale so I do not overfill.the welder supply place I got and fill my tank,I can buy a used tank ($80.00) and switch it
out when empty.I went with the 25lb tank for easier transportability.I used
yahoo search(search words"build your own co2 fill station"or "co2 fill station"
etc")to get the info I needed.