Buy an Apple iPhone 6 Plus outright and you’ll pay $1150 for the 16GB model. Move up to the 64GB iPhone 6 Plus and the price rises to $1300. The 128GB model is $1450. I recommend buying at least 64GB, you’ll soon bump against the limits of 16GB if you store any media on your phone.
You don’t have to pay the full price in one go. New Zealand’s carriers offer lower up-front costs to customers signing up for a 24 month plan. It’s a hefty financial commitment. The most expensive plan on this table will cost $4200 over two years. Here’s a list of the publicly available plans for the iPhone 6 in New Zealand.
At the time of writing 2degrees doesn’t have any iPhone 6 Plus models listed on its site. If that changes, I’ll update the information so bookmark the page and come back. The other carriers report shortages of some models, so you may have to wait to get the model you want.