NALS' is the best post. If your final destination is PC, then you should be able to find a reasonable flight into SD (SDQ). From there taxis will take you a short distance to Las Americas (road) where a guy there directs bus passenger traffic. He will assist you. Just tell him your final destination and do the same for the bus drivers and cobradores. I use plural because from there you will connect to a Punta Cana/Bavaro bus in La Romana or Higuey (prefer Higuey but whichever comes first).
I do this to save like you are trying to do. If your budget is tight then you can save quite a bit depending on the current cost of PUJ flights. Taxi to road = $10 US, Buses combined = less than 400 RD (less than $10 US). The last bus stops at most hotels. Once again, be clear with the driver and cobrador of the second bus on this point.
One final important word of caution, i.e., the cheapest flights are usually the late-day flights. These compromise final destination objectives in two ways. 1) if too late a flight the buses won't be running and, 2) if they are, you'll likely be traveling after dusk (not recommended). I have planned around taking the latest/cheapest flight into SDQ, staying overnight at the airport, and getting a next-day fresh start. There are stores open all night, two large rest rooms, people you can ask questions to, and enough security where you can feel free to take a nap. Before you know it you'll be good to go first thing in the morning. Budget around 4 hrs from the time you leave he airport to PC/Bavaro. Good luck whatever you decide.
