I commute to Boston a few times a week.

Driving is hellacious. Don’t do it. The traffic is awful.

Several folks have mentioned driving to Attleboro station for cheaper parking if you can. However, if you park at the Avalon right across from the PVD station parking is only $13 (before 8 I think) vs the $18 the station lot charges. These days I just take the bus from my house to the station though unless the weather is too bad for me to walk to the bus stop.