This iRobot Roomba 870 Vacuum Cleaning Robot drops from $599.99 to $449.99 at BestBuy.com. Plus, the shipping is free. This is the lowest price we could find for this Roomba by $150. This vacuum is fully autonomous, has a 3-stage cleaning systems, will adjust to clean both hard floors and carpet, and can be scheduled to clean during specific hours or programmed to only clean specific areas. Sales tax is charged in most states.