How convenient (and cheap) is to take MARC from the Baltimore Airport (BWI) to Washington?

I'm going for a weekend trip to DC in July. I'm going to fly into BWI because it is cheaper. I've never to Baltimore or BWI, so how convenient is to take the MARC train from BWI to Washington? Is it fast? Cheap?

MARC from BWI to DC's Union Station (and using Metro or taxi to your hotel from there and around the District) is overall convenient and economical (there is a free shuttle between BWI and the MARC station). There is also a Metro bus line to/from BWI and transferring to the Metro Green line at Greenbelt station as an option. All depends on how much luggage you have and how many transfers you wish to undertake.

IMPORTANT: MARC trains only run on weekdays (M-F); weekends you'll need to use Amtrak (slightly more expensive).

As noted, its cheap & convenient from BWI to Union Station. But, only on weekdays. Otherwise, you can take Amtrak the same route and pay exponentially more for the priviledge.

Its a short bus ride from BWI terminal to the train station. Then the ride to Union Station DC is about 25 minutes.

Next time, fly into DCA. Much better, has metro on site. Worth paying an extra $60 or so...