Buy.com has Wireless Optical Mouse $19.19 + $6.76 shipping.
The HP Wireless 3-Button Optical Mouse is the affordable wireless desktop optical mouse solution that combines functionality with style.
Features
3 Button Optical Mouse-Symmetric Design for Right or Left Handed Comfort and Textured Sides-Optical Sensor 1000 DPI Sensitivity-No Wires to Tangle or Limit Movement-27MHz Wireless Operation-Smooth and Fast Rubber Scroll Wheel
Tech Specs
HP Wireless 3 Button Mouse
27MHz Wireless Operation
Optical sensor 1000 DPI sensitivity
3 buttons: two primary buttons and clickable scroll wheel
Mini USB dongle
Two AA batteries included
System Requirements:
Available USB port
Compatible with Microsoft Windows XP/Vista
Compatible with HP PCs and non HP PCs
Part Number: KY620AA#ABA
Wireless Optical Mouse $19.19 + $6.76 shipping. 
