While it's no surprise that Microsoft would provide a standalone Kinect camera for the Xbox One now that it's been selling the console by itself for a few months now, it's still news that it's gone on sale. So if you picked up an XBONE recently and saved a few dollars by opting for the version without the camera, but now feel like you absolutely have to have it - for some reason - you can now drop $150 and have one shipped to your door.
It's available on Amazon or direct from Microsoft, with the former offering some inclusive deals for the standalone console, though that works out more expensive than just buying the inclusive package with both products in. However both versions of the Kinect standalone package come with the game Dance Central Spotlight.
Microsoft is also releasing other Xbox One Kinect bundles with new games like Assassin's Creed Unity though, so if you want both console and Kinect then those are probably the better ones to aim for, since they come with the game too and that oh so pretty limited edition box.