I am assuming this land is on the way to Yamasa from the city from your descriptions?
I lived perhaps 30km to the north west as the crow flies in the campo in that sort of terrain....possibly the Guanama or a tributary past through an ex esposas family land.
150 tareas is 94,330m2 and the actual price will depend on actual location and if there is any buying interest. If just typical agricultural land work on USD2 to USD 7 per square metre as a guide...say 190k to 650k. But if there isn't a buyer with that sort of cash and the location is not so good location it won't sell easily nor for those sums and it will be down to what one can get.
My current esposa was given 150 tareas of good agricultural land this past Thursday in a share out of family farm land in the northern part of Monte Plata which would be about 50 km north of your location, and whilst it is naturally beautiful location it just would not sell easily unless one of the big ranchers had an interest......maybe not because an aging rancher is selling a wonderful very large area of cattle ranch land with river passing through adjacent and there are no buyers.