Bed Bath and Beyond have both 900 series Roomba on sale starting today thru the beginning of December. Their coupons state that you cant use them with the 900 series but some local stores will allow you. I have the receipt below, but I got the 960 for $480 before tax. You can't come close to that price anywhere else.
My purchase was in Tampa, Fl
$600 -20% 0ff ($120) = $480