iRobot Braava 320 Floor Mopping Robot for $129.99 shipped. Here is a screenshot for your reference. Alternatively, it is available at Staples for $134.99 shipped. It runs up to 3 hours on a single charge using microfiber cloths, and cleans all hard wood surfaces including vinyl, hardwood and laminate. Most places have it for about $249.
Originally posted earlier, this post has been revised and is just a friendly reminder.