State schools are the choice for the vast majority of New Zealand children (85%). Schooling is free at these schools for domestic students, although parents are asked for a contribution to help cover costs of activities that are outside of the core curriculum. Typically this will be around NZ$250- $650. There will also be other charges for sports, school trips [& camps], special tuition, exam fees, and other course related costs. https://www.newzealandnow.govt.nz/living-in-nz/education/school-system
Optional Activities: Parents are sometimes asked to pay for students to attend in-school activities such as performances by visiting drama groups or lunch-time sports or EOTC (education outside the classroom) activities. Attendance at such activities is voluntary, and that attendance incurs a charge.
Charges for Goods & Services: Schools do offer consumables (such as items from the canteen), take-home items (such as items made during technology classes), stationery, clothing, and activities (such as extra lunch time sports tuition, a trip to the theatre) that enhance but are not part of the delivery of the curriculum. https://education.govt.nz/ministry-of-education/publications/education-circulars/2013-circulars/circular-2013-06-payments-by-parents-of-students/