Roomba 860 [bedbathandbeyond.com]
Just bought this in store. Was on clearance from $499.99 to $424.99. Used their 20% off coupon to bring it down to $339.99 before tax.
Its available online too. When you search for Roomba 860 it shows the clearance price in the search results, but the full price when you click on it. Should hopefully show the clearance price during checkout.
EDIT: Now shows the clearance price on the Roomba 860 page as well as in cart.