This company
Regular Flights has flights from sdq to puj departing at 10:00 AM and 5:15 PM for $99.00 US pp one way. It appears that the afternoon flight stops at El Portillo airport near Las Terrenas en route.
A taxi would probably cost that much or more, but if there are several of you it could prove to be more cost effecient. It's about a 3 hour drive as opposed to a 45 minute direct flight in the morning and 1:10 with the stop in the afternoon. Keep in mind also that if you take the domestic flight, you will still need a cab to your hotel after arriving at puj.