This is a very nice hotel in Las Galeras, a small town at the tip of the Samaná Peninsula. The rooms are large and comfortable, with breakfast included and optional A/C. The hotel is only a 3-minute walk from the beach and close to a few nice restaurants, the best of which is actually in the hotel itself: delicious home-made Italian food (try the gelato, made personally by the hotel owner!).
Right next to the hotel there's a small company run by a French couple that offers trips to see the whales (only january-march, $45 per person) and scuba diving trips.
I also recommend exploring Playa Rincón, which is 40 minutes away by motorbike or 4WD.