we will have the day pass at $9/ea = $27 total. round trip regualr would be $30 for the 3 of us, which is cheaper than parking, but we had planeed on the day pass anyways to get around and to the game. thansk for advice though.
The day pass goes up to $14 on July 1: http://www.wmata.com/rider_tools/metro_service_status/advisories.cfm?AID=1086.
The big difference is that they will be valid at all times; previously, with the $9 pass, they were not valid before 9:30 a.m. weekdays.