I had my honeymoon there during June 2002. All expenses added up to SGD7677.12 for both my wife and I.
Accommodation + Airfare : 5189.15 (Changi<>Sydney were on krisflyer redemption tickets)
Tax + Misc charges : 578.30
Insurance : 100
Photography stuff : 350.60 (using film then)
Transportation : 161.86 (includes cab rides on island)
Food : 441.79
Entertainment : 146.41 (shark feeding tour)
Shopping : 709.01 (gotta get that south pacific black pearl)
Did a spreadsheet then... that's why the details!
We communicated and booked online through travel agent in Sydney. Flight there was Changi>Sydney>Auckland>Taihiti>BoraBora>Moorea>Taihiti.
Spent 1 nite at Taihiti, 3 nites at BoraBora, 3 nites at Moorea, followed by 1 nite at Taihiti on way back. Our accommodations on all the islands were at Sofitel chain of resorts (stick to same chain -cheaper deal).. it didn't sound as exorbitant as those USD600/nite as we didn't stay on those luxurious and famous over-water bungalows (sort of regret tho).
Just sharing .. that a trip to such heavon-on-earth place is very do-able.