I can offer you a cheaper option for the Smart Trip card. Baltimore has a Charm Card, it costs $10 with $7.50 on it and it can be used anywhere the Smart Trip can be used. Refills at Smart Trip machines, the Giant, where ever a Smart Trip goes it goes. That $10 will get it mailed free to your door too. »www.wmata.com/fares/purchase/store/
and scroll past the Smart Trip cards and there it is. I had to get another card for an out of town friend and was dumbfounded that I could pay 1/2 price to get a card that did everything a Smart Card did, and on Metro's own site too!--
Simple rules - no offsides, no intent to maim, everything else is all good!