I use a more conventional cylinder that is rated to hold 10 pounds of CO2. It costs about $12 to fill but, compared to that paintball kit, it holds 8 times as much gas. That $12 is buying me an amount of CO2 that would have cost $32 in paintball sized containers, using the price Mikaila quoted. If I had a 20 pound container, it would cost me about $16 to $18 to fill according to the store where I get my refills. It seems they charge quite a bit to connect a tank to their bulk bottle but not all that much for the gas itself. The gas part of my refill charge is only about $6, the rest is the charge to do the refill.