While staying in New Zealand you will be able to find a place to stay practically anywhere you travel. A few options would be Air Bnb, hotels, camper van, Bed and Breakfast, and holiday parks. Lodging varies widely between the different options. On the cheaper end, you can get a place at a holiday park, or room at an Air Bnb for a couple around $36-$60USD. The higher end, would be a bed and breakfast, or hotel for $70-$120USD a night for a couple.
I would highly suggest staying at a place that you have access to a full kitchen where you can cook. New Zealand is a little behind on the internet so it’s very slow. Most places charged us $5 for 24 hours for 1 GB of data. During busy season, I would recommend planning lodging in advanced so you don’t get stuck in a rural area with no were to stay. This is where a camper van comes in handy with so many campsites throughout the country.