There is a massive variety of paintball guns on the market today. The cheapest gun would start at about £49 stripped down. Then you could get a starter package that includes a hopper, air tank and mask for £99 as an entry level price. Most of the time if you are playing on a walk-on rental field you will probably be using a tippmann gun as these are the work horse guns of paintball guns. They can take a lot of abuse and are a standard within the game.