Samana Airport to Casa Marina (Sosua) is probably 3.5-4hrs, and I would guess in the vicinity of $200 (pure guess). If you could get from Samana Airport to Sanchez by taxi, you could take the guagua for around $5 although this onoly leaves once a day around 11:30am.
Gregorio Luperon Airport(POP) is about 15-20 minutes to Sosua.
Not sure where or what Sosua Camino is but Sosua to Maimon would be 45-50mins.
(really depends who is behind the wheel though

)
Can pay in either currency but always negotiate the price before you leave your point of origin.
Good luck.