Costco offers its members the Microsoft Wireless Mobile Mouse 3500 in Gold, model no. GMF-00046, for $9.99 with free shipping. (Non-members pay a $0.50 surcharge.) That's a buck under our February mention and the lowest total price we could find by $7. 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.