Pronouced gwa' gwas.
From Playa Dorada to Puerto Plata or Sosua, you have two options:
1. Guaguas are mostly vans, but recently some of them were replaced by all white buses. If you stand on the side walk in front of the Playa Dorada complex looking like you are waiting for a ride, then the guaguas on the way to Puerto Plata are sure to toot as they approach to ask if you want a ride. Just signal with your hand that you want them to pick you up. If you stand on the other side of the highway, the guaguas on the way to Sosua will toot as they approach.
2. Publicos are cars with a red box on top that says something like PtaPlta-Sosua. They hold a maximum of 6 passengers, 2 in front with driver and 4 in back. They, too, will toot as they approach if you like like somebody waiting for a ride.
If you checked the dr1 news summary yesterday, you saw that prices have just gone up, so I am not sure of what the exact prices will be. But it will be about 15 pesos to Sosua and about 10 to Puerto Plata from Playa Dorada. You pay as you on the guaguas as you near the town you are headed for or, you can feign ignorance and pay when you get out. There is a fare collector on the guaguas who you will see collecting money, so you will know who to pay. Give him close to the required amount, because they aren't good about giving tourists change. You can pay the publico driver when you get out at your destination.
In Puerto Plata, the guaguas leave from the Central Park. When another guagua arrives, the one loading leaves, no matter how many passengers there are. Enroute to Playa Dorada, they will make another stop to pick up more passengers, but it won't be a long stop because another guagua will soon stop for passengers. In Sosua, you can stand anywhere along the highway to get the guagua back to Puerto Plata. Or you can get a Publico at their loading point by the Texaco station, or you can stand closer to the traffic light on the Puerto Plata end of Sosua and get one of the publicos that keeps running back and forth without waiting for a load at the starting point.
We usually use the publicos because you can pay extra to give yourself more room. For example, if you want the front seat alone with the driver, pay 2 fares. Or you can pay 4 fares and have the back seat for you and your companion. This is much, much, much cheaper than taking a taxi. I can take a publico, empty except for me, from Sosua to Puerto Plata for RD$100, where a taxi would charge me at least RD$300.