mwave has Microsoft PS2/USB Optical Mouse (1PACK): http://www.mwave.com/mwave/skusearch_v3.asp?scriteria=BA39923&pagetitle=Microsoft PS2/USB Optical Mouse (1PACK)
for $2.99 + FS for mclub members (free to join)
Description:
Microsoft Optical Technology replaces the old-fashioned mouse ball and works
on virtually any surface. Easy and comfortable to use, Basic Optical Mouse
is a good choice for value.
Now you can experience the benefits of the world's most powerful optical
technology. The Microsoft optical sensor replaces your old-fashioned mouse
ball. The ambidextrous design is comfortable whether you mouse with your
left or right hand.
Features:
# Connectivity - USB&PS2
# Cable Adapter - PS/2
# Button Count - 3 Buttons
