Depends where your playing, Most sites will give out some kind of jackets or coveralls to pretect your clothes, most importantly i would advise good footwear, i use rugby boots because of the ankle support. If your playing somwhere that dosent offer coveralls, and don't want to spend 100 odd notes on kit, then just some old, confatable fitting clothes. Baggy is always good as you are more likely to get bounces
and they let you move that little bit more.
-Joe