Office Depot has the Microsoft Wireless Optical Desktop 1.0 for a very nice price.
Go to this page and add the Wireless Desktop (with Price of $29.99) to your cart
View cart and add coupon 65736273 (this coupon will take 10% off your order)
Choose to pickup in-store to save on shipping.
There is a $10 rebate that you can submit to save you $10.00
Final Price is $16.99 After Rebate. Not bad at all!
(PS: I had the wrong link up before. This should work.)