Semis the most expensive. Regular players usually own Camo of some description. Some choose ex army Camo or new camo of standard military design. Others choose camo specifically designed for paintball. The options are many and varyed.
Strong boots are a highly recommended item - again the options are many and varied.
There are two variations of the tag rule. When you have been tagged you must stop shooting. Just because people aren't actually shooting at you does not mean that you won't get hit by accident. Most social games are played using Recycle rules. I'm going to leave this one blank for now.