OnLive's confirmed that anyone who pre-orders Batman: Arkham City with it will get a free Micro Console for the service. The game is at £39, but is available to pick up for £27 if you are subscribed to the PlayPack coverage. The console itself has an RRP of £70, but most people will have picked up a free console from EG Expo last week, let's be honest. If the console doesn't interest you, you can wish to receive another game for free when you do your pre-order.
More details here.