Amazon has the Logitech G400 Optical Wired Gaming Mouse for 
$21.75 w/ free shipping on orders over $25. 
 
    3600 dpi optical engine: Get precision targeting, pinpoint accuracy and consistent response at any hand speed
    In-game sensitivity switching: Four dpi levels let you instantly go from pixel-precise targeting to lightening-fast maneuvers
    1 millisecond report rate over USB: Mouse movements are communicated to your PC at a blazing-fast 1000 reports per second
    Built for battle: Comfortable sculpted grip, low-friction feet and rugged long-life buttons that withstand demanding play
    Made for PC gaming: Compatible with Windows XP, Vista and 7