It is an easy site to navigate, and you can purchase tickets in a few different currencies, including NZD and AUD. They have an 'Invite a Friend' function where you get NZ$4.70, and the person signing up gets NZ$4.70 (currently works out to be about $3.27 USD).
Here is my referral link so that we can both share in the rewards of this great site:
If you have downloaded their app, follow these instructions:
1. Create an account
2. Click on 'Mine' and then 'Promotions'
3. Input 7X7I7
Although NZ$4.70 doesn't sound very much, remember this is already off heavily discounted standard prices for attractions. If you're travelling with your partner, a family, or a group, if you use the 'Invite a Friend' function to get others in your party to join and share in paying for tickets, then the savings will build up (although note that you won't get your NZ$4.70 until your friend's booked experience is completed, but you can obviously put this towards another booking in the future).
Thank you to all who have signed up via the above link thus far!