Avalon Direct via Amazon offers the iLife A4s Smart Robot Vacuum Cleaner in Gray for $199.99. Coupon code "369MC7DO" drops that to $159.99. (Fastandfurious06 via eBay charges the same, although it ships from China.) With free shipping, that's the lowest price we could find by $23. It works on all floor types and features a HEPA filter, 3-step cleaning system, 120- to 140-minute runtime, and automatic docking and recharging.