There are several ways. The most convenient is on www.trademe.co.nz where you can find hundreds of listings.
Otherwise, there's a cool little place off Karangahape Rd in Auckland, called Backpacker CarWorld. Most cars range between $2k and $3k, but a legal and mechanical check is highly recommended ($200).
The car auction in Ellerslie (Auckland) is another very popular option. about 6 years ago
Hi, when you get your car or campervan just be aware that they are some timnes targeted by petty thieves. Especially if you leave it at a trail head and go hiking. The thieves figure they'll be loaded with all your cameras and laptops.
Phil from the safety hub about 6 years ago