Re: re:taxi or other transportation to decameron b
Depending on how far that beach is from Las Americas, you could hire a taxi to take you there or hire a taxi to take you one of several bus stations, like Caribe Tours, in Santo Domingo, and then take a bus to your destination. Cost of taxi, depending again on distance, will run you $200RD or more to get out of the airport. Cost of bus could be as cheep as $60RD.
Or you could rent a car from a brand name rental car agency (Hertz, Budget, National) stationed right there at the airport. Prices are similar to US - $40/day including mi/km. In fact, you can make a reservation in advance, and the vehicle will probably be available when you arrive. BUT they try to get you to add insurance, another $10/day or more, which is not always necessary if you have car insurance on a vehicle that you own...AND the roads are not similar to US. So TAKE CARE!
I'm sure others have more ideas for you. Good luck, Sarah