Originally Posted by wahooflyer
For those of us who are really on a budget, there's also free street parking right near the airport, on the shoulder of Elkridge Landing Road. You can walk to the daily garage from here and take the free shuttle to the terminal. Don't even think about trying this in winter, though, as I've seen mounds of snow piled up alongside Elkridge Landing Road after storms. It might take days for you to dig your car out.
Depending on the time of your flights, you can also park for free at Arundel Mills Mall and catch the Howard Transit shuttle to the airport for $1.25. I think they only run every 45 minutes though and they don't run past 11:00pm.
I know there is a parking lot for the Dorsey Road light rail stop and it is in a very safe area and very well lighted but that train doesn't go to BWI. I'm not familiar at all with the light rail system. Only used it once to go to an O's game.