Ryan
Court Jester
Guest rewards for free travel is pretty easy.
But, you've identified the problem with monthly passes and AGR - you only get a point per dollar spent, do you'll end up building points up very, very slowly.
If you have a MARC monthly pass from BWI airport, you can get a free card to use the garage at BWI for free. You can get a BWI-BAL monthly pass for $100/month. I think that parking in the BWI garage will run $9/day, so it would be cheaper to buy the MARC ticket than pay the $180/month in parking (assuming I'm right about the $9 and you average 20 workdays per month).
But, you've identified the problem with monthly passes and AGR - you only get a point per dollar spent, do you'll end up building points up very, very slowly.
If you have a MARC monthly pass from BWI airport, you can get a free card to use the garage at BWI for free. You can get a BWI-BAL monthly pass for $100/month. I think that parking in the BWI garage will run $9/day, so it would be cheaper to buy the MARC ticket than pay the $180/month in parking (assuming I'm right about the $9 and you average 20 workdays per month).