Under 9-1-1 regulations, towns are required to provide a road name sign where the private road meets the public road. For town ways, signs are supposed to be green with white lettering. To distinguish private roads, signs are supposed to be blue with white lettering. But many towns ignore that requirement. It would make things less confusing if all towns followed the same system.
Once you are within the subdivision, I don't believe the Town is required to provide further signs. If you can get them through the Town at the Town's price, that's probably your best bet, as they will be uniform (and cheaper!) If not, there are places you can go online and order custom signs.