Best Buy via eBay offers the Ecovacs Robotics WinBot Window-Cleaning Robot in Champagne, model no. W710-R, for $179.99 with free shipping. That's $20 under our mention from two weeks ago and the best price we've seen. (It's a current low by $55.) It utilizes an on-board computer and multiple sensors to calculate the size of your window and program a custom cleaning path. It features an approximate cleaning path of 9", 1-button operation, two cleaning pads and squeegee, and remote.