BestBuy and Costco in Orland Park sold out of sensors and low supply on 4GB and 250GB bundles.
As for the ebay prices I dont think you will see the sensors marked that high with the 4GB bundle at $300. Might as well get a new Xbox with the sensor at $300. So until the 4GB sells out the sensor prices wont get above $200.
Its libraries that sell systems not a single game.