For heaven's sake! I wasn't sure if the book I was thinking of buying was NZ$2.49 or US$2.49 (NZ$4.21) but at that price it doesn't matter. On clicking Buy I had to log in, only to be greeted with a 100% price hike to NZ$8.11 and this message:
The price for this Kindle book is different for your country/region and is displayed below.
Bah! No buy!