Amazon has the Microsoft Mobile Memory Mouse 8000 Mac/Win for $25 with free shipping.
Technical Details:
* Transceiver with 1 GB Flash Memory - Also a fully functional flash drive, so you can store and transfer files and free up USB ports
* 2.4 GHz Wireless Technology - Connects wirelessly right out of the box with virtually no interference, and up to 30 feet of wireless range
* USB Rechargeable with Magnetic Connectors - Simply snap in the magnetic connectors to charge while working, using the included USB transceiver
* High Definition Laser Technology - More precise, more responsive, and deliver smoother tracking
* Battery Life LED Indicator - Glows red when the battery is running low
Amazon.com: Microsoft Mobile Memory Mouse 8000 Mac/Win: Electronics
Microsoft Mobile Memory Mouse 8000 w/ 1Gb Flash Memory (Mac/Win) $25 + FS 
