It depends on where you are going. If, as your post suggests, you are out in Bavaro/Punta Cana, then you are slightly limited. If you can find a "FUMO" cigar store, I can recommend them as fair priced and good stock.
There used to be a sort of Cigar Museum between Bavaro and Hig?ey, but I don't know if it still there. If it is, you will find good cigars there.
Maybe others, more versed in the area can help you.
A day trip to La Romana's Columbus PLAZA, which I have mis-named as Caribe Plaza before, is worthwhile. They have all Dominican made brands..and fairly priced.
Good luck,
HB