Best Buy offers the Microsoft Wireless Mobile Mouse 3500 in Black, model no. GMF-00030, for $14.99 with free shipping. (Amazon charges the same via Prime). That's the lowest total price we could find by $5, although we saw it for $5 less in a different color in December (which required pickup). Sales tax is added where applicable. This wireless mouse features BlueTrack technology (which purportedly works on more surfaces than optical or laser technology), a nano transceiver, on/off switch, and more.