Springs Electronics via eBay offers the Microsoft Touch BlueTrack Multi-Touch Mouse, model no. 3KJ-00001, for $9.99 with free shipping. That's $6 under our April mention and the lowest total price we've seen. (It's also a current low by $7.) This mouse is sensitive to 1-, 2-, and 3-fingered gestures and features BlueTrack technology, 10-foot range, and 1,000 dpi. It requires Windows 7 or 8.