If I want to buy my own camouflaged gear should I buy to sets of tan and green or if, say I only buy green will I then only be allowed to be on the green team. Basically should I buy my own gear or should I rent from them.

You have to have your own camo. Many people have at least two sets, people that are part of a team dominantly have one color but regularly switch out for a change of pace. Start with the one you like the best and then later add ah least one set of the other. Or find a team and see what their color is.

It helps to have both colors of camouflage

They don't rent out camo, but in general what they provide is good for a day, if you don't wear camo you are put on either team or on one team if you wear the colors of a team