Microsoft has announced a price and release date for the new Kinect v2 on PC. The motion device will launch on July 15 for $199.
The Microsoft Store (via IGN) is selling pre-orders for the device. Like the first Kinect, the PC version is likely to be used for purposes beyond gaming. The product description notes that developers can use it to build "interactive voice- and gesture-based applications for the Windows desktop and Windows Store."
Keep in mind that you can't plug this in to your Kinect-less Xbox. It may give us some idea of what to expect for standalone pricing, though, as Microsoft's Phil Spencer has previously said that buying the Xbox One and Kinect bundled together would be cheaper than buying them individually.