thanks for the thought stinkbud.but i will let you in on a little secret also. the majority of us already know about co2 tanks and buying the refills at walmart for paintball guns is 1 of the most exspensive routes. i have a i beleive 20 gallon tank sitting on my porch right now that would not cost you near that to refill nor would be the regulator to adjust airflow. not trying to embarress you in anyway, because it was awfull nice of you to try and let us in on your secret but please try to read a little bit more in sections that you post in to make sure its not already in there . and if you really wanna know the cheapest methods , it would probably be the baking soda with vinegar or the quick rise yeast mixed with sugar in a empty 2 litter bottle. either method would work very cheap.