I have been having my eyes on the Neato XV-21 and iRobot Roomba 630 from Amazon US. But what I found is that prices actually went up during the period between US Thanksgiving, Black Friday and Cyber Monday period.
Roomba 630 : price went up from $299 to $349
Neato XV-21 : Same price but shipping to Australia went up from $65 to $79.
Just a marketing trick I reckon.
Not sure about Neato XV-21, but according to Camel x3, iRobot Rommba 630 was only at $299 for one single day (Nov 27), and it has been at $349 most of the time.