If you are an avid paintballer then you know that some paintball parks like to charge big bucks to refill your co2 canisters. Some parks will charge five dollars per refill on a 20 oz tank and some will charge a certain amount for you to get “all day air”. Most people don’t realize that co2 isn’t that expensive and you can get it much cheaper. The reason it is so expensive at paintball parks is because you are paying for the convenience of having it near by, you just have to pay.