The overall pricetag for the Circle Line would likely be in the range of $14.5B - $18.7B. This was determined by using an average cost per mile range of $850M - $1.1B.
Everyone in Massachusetts would need to do their part and pay a portion of the cost. That means individuals, corporations, non-profits, communities - everyone.
The method to pay for this project would be 5-pronged: