Newegg via eBay offers the Acer DA220HQL 21.5" 8GB Touchscreen LCD Monitor / Android Tablet, model no. UM.WD0AA.A01, for $179.99 with free shipping. That's tied with our mention from a month ago and the lowest total price we've seen. (It's also a current low by $62.) When plugged into a PC, it acts as a touchscreen monitor and when unplugged, it doubles as a 21.5" Android tablet. It includes a wireless mouse and keyboard and features a 1GHz dual-core processor, 1920x1080 (1080p) touchscreen LCD, 1GB RAM, 8GB internal memory, 802.11n wireless, Bluetooth, two USB ports, micro HDMI, and Android 4.0 OS (Ice Cream Sandwich). Deal ends January 5 at 11 am ET.
Note: It's not guaranteed for delivery by Christmas.