Those working in hotels earn a weekly wage (around NZ$10 per hour).

Those working at the Airport get a weekly wage starting at around NZ$10per hour.

Those on the Stud get accommodated and paid around $600/week. 

Work in the Schools is voluntary but accommodation is provided in a local homestay, and you do get paid a little pocket money. 

The farm work is voluntary.  However, often the farmers do give their volunteers some 'pocket money'.  This will only be enough to buy you a few provisions and the occasional beer and is entirely at the discretion of the farmer.  You will need money brought from home - especially if you want to stay in town or travel during your free time.