Thank you for the info.
Last time I went to Boston, arrived on United, I couldn't find the place to purchase a pass, I think I paid $5 directly to the bus driver.
This time I will arrive on Delta, I hope I can purchase a week pass at the airport, so I don't have to pay extra $5 for Logan Express.
On the way back, my flight was 7am, so I had to take a cab because Logan Express back to airport start at 5am, and with tight security at Logan Airport, that was too late.
According to airport staff, between 5-6am is the busiest time at TSA security checkpoint at Logan because a lot of flight depart around that time.
Line was so long and took me at least 1 hour to clear the security. They don't let you go to the front even your departure time is close.
If you travel by the air, I suggest you go early.