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Amazon: Batman Dual pack: Batman Arkham Asylum GOTY and Batman Arkham City $10USD*(r/GameDeals)
You get steam keys for both games.
25% off Promo Code: OCTOFUN1 (One use per amazon account) can be used on this pack if you haven’t used it already on BF3 or Fear pack or etc.
Cheers to Tony
*edit if you get deal is unavailable try: www.amazon.com/Batman-Arkham-Action-Pack-Download/… or the * Electronic Frontier Foundation link