Batgirl DLC for Batman: Arkham Knight information
Batgirl: A Matter of Family will release this month on July 14th. The story based DLC will take place prior to Batman: Arkham Asylum, making Batgirl finally playable for the first time in the series. The DLC will cost $6.99 or can be downloaded through the purchase of the season pass for $39.99. Expect much more DLC for the next 6 months as explained in the season pass details.
Original source: Game Informer