So just quickly.
Boston has its own smart card system. The machines, however, do not dispense the smartcards. A personal fancy of mine is to quickly adopt the local cities ticketing system. Smartcards tend to keep you out of strife when commuting and just make things simply easier.
I collected a free one from the information/ticketing desk at Central station.
You’ll need to go down to the subway concourse to load up some money onto the card.
Bam. Subway and busses catered for.