Parking at an airport parking garage, the only option within walking distance of the terminals, will cost you about USD 240 for that long ($24 per day/$120 per week, after the first day anything over 6 hours counts as a full day). Not a good idea.

The Logan Hilton is right in the middle of the airport, by far the closest, but I don't think (check to be sure) they offer a stay/park/fly rate. The Hyatt is nice, and is technically on the airport property, but is so far away from the terminals that it almost might as well not be.

If money is a concern, I'd go for an off-airport hotel with a stay/park/fly rate. You'll find most of them by searching in the city of Revere. I've heard good things about the Sheraton Four Points there, if you stay in the new part. Their program includes two weeks free parking. If you're a CAA member you should be eligible for their AAA rate. (I don't get any commission from those folks, and this is second-hand info.)