Some require a torso hit while at others, the referee will call you out even if only your gun gets hit. Like any sport, the initial cost of getting what you need to participate can shock you. There are different barrels that can be substituted to inprove accuracy, different size gas tank etc. While it may be somewhat expensive, having your own equipment allows you to 'walk on' at many paintball resorts. Since they do not need to plan for the renting of equipment, you don't need to wait out the 2 to 4 week required reservation period in most places before your day of fun.
Some places also require a down payment or even paid in full two weeks in advance.
If you have your own equipment, just go. You'll find a team to play on. The largest of the on going expense is a supply of paintballs. They run all over the lot in price. One can order real cheaply right here on the Web.