There are cheaper alternatives. Buses to Cabarete and local guaguas that go up and down the coast with no hassles...
We fight all the time as to the best way to get to Cabarete from the airport.
If you rent at the airport go to the left as you leave the terminal (towards the Fed Ex offices) and go straight. At the end, turn left again,and go to the end. Then about 14 kilometers as you start to come into Moca, there is a major road that comes in from the left (almost the only one), and you take the left. You should see a Texaco on your right maybe 100 yards up the road...
Anyway, that road goes to the Jamao crossroads. There is a small green police station
on your right, and you take the right and go up the hill and follow the road until it reaches the North Coast highway...then you turn left once more and get to Cabarete in about 5 minutes.
HB