Traveling by car in New Zealand is the best way to explore this gorgeous country. The other options such as buses or hitchhiking reduces a lot the flexibility to explore the hidden spots, gravel roads, and coastlines. If you are going to stay for at leat 3 months in the country, buying a car is a great idea, considering you can find good deals and use the car as your own accommodation. I bought a Nissan Sentra 1995 with lots of kilometres but a well maintained car for only 1400 New Zealand Dollars. This car is a wagon type which allowed us to set a double bed in the back.