Hi:
I am not sure of the exact location in Samana. The main supermarket will carry a selection of imported wines. There is probably also a liquor store or two in town. You can by bottled water at any market. There is a large selection. Most people staying for a while buy the 5 gal jug, which costs around 50 pesos(about 1.25US) and a hand pump or you can buy liters or gallon bottles but they probably will cost as much. If you are coming to Las Terrenas, Supermarcado Lindo has a large selection of Italian, French, Spanish, Chilean and other choices of various quality wines. It is located on one of the main streets in town.
S