Currency in Pitcairn Islands New Zealand dollar (NZD NZ$). For 10 US dollars you can get 17.7 New Zealand dollars. For 100 US dollars you can get 177 New Zealand dollars. And the other way around: For 10 New Zealand dollars you can get 5.66 US dollars.
Prices:
And if the trip plans are simply for a given region of the world, then maybe it will come out cheaper than in Pitcairn Islands in nearby countries? See prices in: French Polynesia, Cook Islands, Niue, American Samoa, and Samoa.