I've been there twice... the first time on business so the company paid the most expensive piece, the flight. Second time I went on vacation and because of the remoteness of the country, flights can be pricey. However, once you're there, the exchange rate b/ween the NZD and most countries is quite favorable so much of your expenses are reasonable. Depending on your preference for lodging, you can find some pretty darn reasonable hotel options. Everything else is pretty inexpensive thanks to the exchange rate.
I'm not sure where you're located, but if you don't like to fly, be prepared. From the East Coast of the US, it could range from 19 to 22 hours, depending on your stop-over.
Personally, I highly recommend it... I don't know anyone whose gone and has NOT enjoyed themselves.