As far as gear, it depends on your budget. Some camos, a mask or pair of goggles or even shooting glasses, and a gun is (in my opinion) all you need to start out. As far as camos, any hand me down store like Salvation Army, Savers, or surplus stores are best. Masks, walmart has em, cheap and simple. As far as guns, the best out there for the cheapest price are G&G Combat Machines and Lancer Tacticals. (though I haven't heard a definitive verdict on them, Lancers do have beast internals, and for $100 it's a great starter.) And yes, learn the rules of the game.
If you have any other questions, the forums are the place to ask. Enjoy, and welcome!