Son graduated in '12. No mandatory fee to play. Parents were asked to run the concession stand for one game - no big deal if you could not. There was usually a fundraiser to help - the last few years the players were selling cases of soda. Parents are encouraged, but not required to join the booster club.
A couple of years back the school division debated on instituting a "pay to play" fee to help offset the athletic expenses, but it was tabled and has not (to my knowledge) been brought up again. Some of the neighboring school districts (counties) have instituted a play-to-pay fee. At one school system it is $100 per student per sport so if a student plays three sports it's $300. As I understand it, the fee is not due until the final tryouts (if any) are completed for that sport. There are exceptions for students/parents who cannot afford to pay.