If you go to Massport.com they offer parking on Fargo St. for cruises. I used them for a September 2023 cruise - I don’t remember exact price for parking for my 11 day cruise, but it was around $200 or so. They have shuttles that run back and forth from the cruise terminal. It’s surface parking in a fenced lot - when I arrived around 10 AM there was no attendant to tell you where to park, I just pulled up to a car already parked there and put my confirmation on my dashboard. By the time I pulled my luggage out of the car, several others had parked and one of the shuttles had arrived. If you feel like dragging your luggage, you can walk to the port - it’s about two blocks.