One of my step sons is in a state school and the voluntary fees came to just over $300 for us too. We didn't pay it last year and haven't this year. Last year we were about to have my daughter (who was an IVF bub) so we were pretty thick in bills, and this year we are close to having our surprise bub, so again we've got quite a few unexpected bills. I was surprised last year when we didn't pay them and then received an invoice for them from the school. To me "voluntary" means, well... voluntary! So I never expected an invoice. We didn't do anything about it though and it was never chased up with us.

My other son is at a specialist private school so his fees run over $10grand and none of it is voluntary :/ Hopefully this year we are able to get government funding though so it won't cost us quite as much.