Today only, get up to 40% off iRobot Cleaning Robots at Woot. Shipping adds $5. For example, the iRobot Roomba 621 drops from $429.99 to $259.99, which is the best price we could find online by $135. This robot has a three-stage cleaning system. It features iAdapt cleaning technology and Dirt Detect, which both find and remove dirt, pet hair and other debris. The iRobot Roomba 645 is also the best price online by $15, dropping from $429.99 to $329.99. This robot has twice the battery power of other Roomba's, while also featuring the same three-stage cleaning system with AeroVac. Sales tax is not charged in most states.