When we were planning our route from our stop between Salem and Boston to Niagara Falls (US side) but weren't able to find an easy answer for people wanting to find out the toll cost for a car driving from the Boston area to Niagara. For this route it turned out we were saving close to two hours compared to the non-toll routes so decided to take the plunge and go anyway - a 7-and-a-bit hour journey is long enough for one day's driving.
The total toll for this route from Salem (or Boston), MA to Niagara, NY is $21.60. Here is the breakdown:
Here is a screengrab of our route (Boston on the right, Niagara, MA on the left) in case that is useful for making sure your route is similar:
Hope this helps! If you are driving across the US, or visiting Niagara falls you might find some of our other USA travel articles useful too :)
Just in case you are in a rush - we normally can get back to you in less than a day!