Earlier today GameStop posted the release date and prices for two character bundles and a Batman skin pack.
The first DLC due out for
Batman: Arkham City is the Nightwing character pack which is due November 1st and will cost $6.99. Nightwing is the only character not part of any game store exclusives so it makes sense to have his DLC come out first.
The second DLC due out is the Robin character pack which will be released on November 22nd and will also cost $6.99. This Robin DLC is available as a pre-order bonus from Best Buy and will include alternate Robin skins and two challenge maps.
GameStop's pre-order exclusive Joker's Carnival, is also expected to be released along with all of the other game store exclusives.
The third DLC due out is the Batman skin pack which is released on December 6th and will cost only $4.99. GameStop did not list which skins will be included in the pack.
These were taken down by GameStop soon after they were posted on their US site which probably means someone jumped the gun.
Batman: Arkham City is set to be released on October, 18th.