While New Zealand might not be one of the cheapest countries, it’s definitely one of the easiest to move around.
Apart from domestic flights, travelers can buy bus passes from different companies. These passes allow them to hop on and off for a limited amount of time. Another option is to just rent a campervan and drive at your own pace staying at the many camping grounds and caravan parks available.
If you’re short of money, don’t worry, you can always go to the side of the road and stick your thumb up. Hitchhiking is super common and extremely safe.