I did not have a chance to come and to look at the recent amount of rates to the Ambon- Ambon Falls due to the limited time. But I was able to find a site wherein the rates of it are posted.
According to http://www.backpackingphilippines.com, the following are the amount of rates in August 2011.
The Entrance Fees in Ambon – Ambon Falls
– Day rate (6: 00 A.M. to 6: 00 P.M.): Ᵽ 40.00
– Night Rate (6: 00 P.M. to 6:00 A.M.): Ᵽ 80.00
– Overnight Rate (more than 12 hours but not more than 24 hours): Ᵽ 100.00
– 2 Days /1 Night Camping Fee Per Person: Ᵽ160.00
– 3Days / 2Nights Camping Fee Per Person: Ᵽ 240.00
Other Fees and Charges:
– Trekking to Biak-na-Bato/Ambon-Ambon falls (tour guide): Ᵽ 60.00
– Environmental Fee: Ᵽ 1.00
– Development Fee: Ᵽ 1.00
Cottage Rental Rates:
– Small House/Cottage: Ᵽ 200.00
– Big House: Ᵽ 400.00