While Microsoft haven’t publicly revealed a price for Kinect, a Gamestop listing prices a standalone purchase of the device at $149. Bundled with the new Xbox 360, however, the purchase will cost $299 or $399, depending on whether you opt for an Arcade bundle or an Elite bundle.
Additionally, it would appear Kinect launch titles Kinect Adventures! and Kinect Sports will retail for the usual $59.99.
Many thanks to Christopher Barth for the heads up!