We have voluntary contributions and fundraising. TBH I think that to a large extend the fundraising catches the shortfall in voluntary contributions.
I pay the voluntary contribution and help out with fundraising when it's not too onerous but it does make me kind of bitter that so many parents at our school seem to think that other parents should be subsidizing their children. I get that not everyone can afford voluntary contributions but I suspect that at our school there are only a few families that are genuinely unable to pay.