Not long ago, Microsoft took the Kinect out of some of its Xbox One bundles, dropping the price of the console to $400 and giving devs extra power to play with. If you got one of those and want to add a Kinect later, you'll be able to in October, for $150.
That Microsoft would offer the Kinect as an add-on for the Xbox One is no surprise, and neither is the fact that it'd cost extra so that the bundle still makes some sort of sense. That extra $50 will also net you a copy of Dance Central Spotlight though, and historically Dance Central has been pretty much the only game worth playing on Kinect anyway. Whether or not that's enough to save the Kinect as a viable input device is still up for grabs, though still pretty unlikely. But adding that game in the bundle is a great way to make picking up a Kinect a liiiittle more enticing.