Really good mouse and has some good reviews.
Have checked other sites and couldn't find any cheaper.
Microsoft Arc Touch Mouse (Specs below)
The mouse that fits in your pocket. The mouse like no other: it is unique in look, feel and performance. The innovative design curves for comfort when in use, and packs flat like a small cell phone when on the go. The touch-enabled scrolling allows you to flick to move quickly up or down on the page and tap to stop. Feel the speed and responsiveness to your touch. You can use this mouse on various surfaces—rough or soft with the Bluetrack™ technology*. The unique design saves battery life: curve to turn on and flatten to turn off.
*Bluetrack™ Technology does not work on clear glass or mirrored surfaces.
Microsoft Arc Touch Mouse Features:
Flexible Design - Curve for comfort, flatten to pack.
Touch to Scroll - Click. Tap. Flick. Control.
BlueTrack Technology - Works on difficult surfaces—rough, glossy, or soft.
Perfectly Portable - Stowable Nano Transceiver for wireless freedom.
3-year limited hardware warranty.