If you are willing to spend $70-$100 you can purchase an entry-level semi-automatic or electro-mechanical paintball gun and all necessary equipment to play. While many guns come in a package with a hopper, mask and tank, you can also by these accessories separately. Masks start at around $20, CO2 tanks
start at around $12 and hoppers
at about $5.
Some basic guns are non-upgradeable while others allow you to add expansion chambers, improved barrels, drop forwards and other upgrades. You may also want to consider purchasing some paintball-specific clothing from a thrift store or an army surplus store.