Kiki, this is a public school team. You pay $150 per sport for your kid, and I'm not exactly sure what the money is used for. Most CA school sports programs have been gutted financially, and there are very active parent booster clubs that fund raise to make up the gap. They are fanatical about fund raising! Not my cup o' tea, but I do think for students who have no money to spare, not to be able to play a sport at a public school is wrong. I guess the fundraising is a necessary evil.
I would guess insurance, field/court maintenance, equipment, uniforms? Entry fees, coach's time... Things like that?