Yes, there is a bus that runs 7 days a week from Puerto Plata to Samana and will pick you up if you wait along the highway and flag it down. It is basically maroon and has a big Puerto Plata-Samana sign by front windshield.
If in Sosua, you should start waiting on the highway about 6:50 to be sure of catching it. In Cabarete, shortly thereafter. No terminals in Sosua or Cabarete, people who want to ride the bus flag it down.
When you return, the bus leaves Samana at 2 pm from across the street from farmers market. Until !:45 it is wating by the central park.
