Your most important piece of equipment. You can play anywhere with one and no where without one!
There are a huge variety of masks on the market today, ranging in price from about $15 to over $100. You’ll be wearing your mask a lot, so think seriously about getting one that fits well, allows you to breathe well and provides good, all-around vision, and worry about the expense later.
Check into the cost of replacement lenses for any model you intend on buying also.
Masks should be stored in a protective bag in order to keep the lens from getting scratched.
Goggle manufacturers recommend replacing your lens any time you’ve received a direct impact from a paintball, or once a year (at a minimum). Vision is important, so you’ll want a clear lens in your mask. Safety is even more important, so replace used/questionable lenses as soon as possible.