I went through this a year ago. After researching Sosua to Puerto Plata to Gaspar Hernandez, I found a basic bike at a good price. Gaspar Hernandez, just as you are entering the town, on the right.....Bikes on the street on display.....Stop and talk to the sales people. I sent my Haitian gardener and they treated him bad and wanted a high price. I went and talked to them myself. They didn't have what I wanted....a basic, no gear, heavy duty bike. They sent me across the street to their warehouse, and, voila....there one was. No negotiating. Good price. (Can't remember, but I searched all across the North Coast and the best price was there.) I now have a one gear, heavy duty bike for my gardener to use.
If that is what you are looking for.....this is the place to go.
Good luck!
Lindsey