Joystiq has been in contact with the person who uploaded images (to HighDefDigest.com) showing a "new low price" of $299 advertised for the Xbox 360 in a Kmart flyer, beginning the week of July 6. He snapped the images quite quickly and they've slowly begun spreading across the internet.
We're currently attempting to confirm this information with some of our other retail contact, while our source is attempting to get a full page scan of the Kmart flyer. There is still no word on how this $50 price reduction on the Premium model will affect the Arcade or Elite Xbox 360 consoles, currently priced $280 and $450, respectively. More images can be found after the break. We'll update as soon as we learn more.
Update: Full-page ad pictured here.
[Thanks to everyone who sent this in; with special thanks to that "Anonymous" someone!]