There may be a simple reason Amazon, GameStop, Best Buy, Walmart and others are pricing Kinect for Xbox 360 at $149 USD. That's how much it costs Microsoft to make the thing, according to a new report.
Develop cites a "highly-positioned, trusted source" who considers the price of Kinect for the Xbox 360 "a topic of concern for his company," presumably if it's sold at its currently rumored price (or higher). The cost of entry for Kinect may be lower for consumers if they buy one of those Xbox 360 bundles, but it still raises the cost of Microsoft's console by $100, if you want to play all that new software.
Microsoft has not yet announced a price for the motion control add-on and may still be figuring out just how much cash it wants to lose on the device.