Most paintball fields have free fills if you pay the entry fee but not all fields are the same and prices will definitely vary.
Air is never too expensive though, It wouldn't ever be more than $5 / £2.50 (aprox)
T-Square Paintball, Jacksonville Arkansas
29 dollars for refill
Yes! The purpose of an Air tank is so that you can refill it. Almost any Paintball Field or store can fill your tank.
If it has threads on the top, you refill it like any other tank by taking it to a sporting goods store or paintball field. If it does not, then it is a disposable, and you cannot refill it.
Call them and ask!
Dicks, any paintball shop, and Gander Mt.
Only if it can produce 3000 or 4500 PSI . Take it to a paintball store and normally they give you a fill for a dollar or so. If you are playing and you need to refill, go to the refill station, attach the fill hose to the air nipple while the tank is on the gun, press the lever or button until it is filled at the correct pressure.
All paintball guns require propellant, but some use HPA or high pressure air, instead. HPA tanks are more expensive and holds less shots, but are significantly more consistent (accurate) and easier and cheaper to refill. You can also tell how much you have left on a HPA tank.
In a perfectly mathmatic world: 4. Realistically 2 and a half just from leaked air and lack of pressure after fills.
Yes, every few games, you will have to refill the tank, depending on the size. Without it, there is nothing to propel the paintball.
I'm going to include paintball rifles in this answer. The cost of paintball rifles can exceed $500, but your question only refers to C02 powerplants. So in this answer paintball generally out cost regular C02 pistols and rifles. Now if you include all power plants like Pump, spring and PCP. (Precharged Pneumatic) air weapons then Pellet pistols out cost Paintball. As for the sport itself, with the cost of protection gear and the cost of gaming in general, then Paintball out cost regular C02 in general. But remember paintball is a competitive sport where teams compete against each other and shoot each other. Pellet shooting is a target and hunting sport, they are two very different sports and really should not be compared. Getting shot with a paintball won't kill you, getting shot with a pellet can kill you.
A paintball is roughly a sphere and will have a drag coefficient of ~0.1