MetroCards cost $1. All cards except for the Single Ride card are refillable. Up to three children under 44 inches tall ride for free when they're with a fare-paying adult. You pay the fare at turnstiles before you board the train. You don't have to do anything after.Where to purchase Metro cards?
A: You can buy SmarTrip cards at any of the four Arlington locations of The Commuter Store, at the Mobile Commuter Store, or online from Commuter Direct.com for $5.00, with no fare value. SmarTrip cards are also available at Metro sales offices and at retail outlets.