There are costs to be considered both ways. After a fairly lengthy quote process, I found costs of ferry to be about half of a water taxi. Both methods of transportation have hidden costs, like extraneous land taxi costs, baggage fees and taxes. But on average, figure $90-100 per person for ferry and double that for water taxi per person, each way. Costs for water taxi can go way up if you wait to make the reservation. Last minute reservation can get very pricey.