The $22 USB Optical Mouse with Pocket Digital Scale is capable of handling a weight range of 0.1 gram to 500 grams. Since it is ergonomic, it works for both right-handers and southpaws without missing a beat – although gamers might want to avoid this since it is purely a working man’s mouse, and won’t have any special buttons to fire off a macro command or anything like that.
The scale will need a couple of AAA batteries to run – strange as to why they can’t make it rely on USB power alone, so you have less stuff to tote around.