Hi there,
I am pleased to say I just got a USB Microscope a few weeks ago, and am very happy with it so far.

That is the one I got off
ebay for around $35 and it arrived from the vendor in Hong Kong safe and sound.
I haven't done much with it so far, but here are a few screen shots that I have made and can share with you. The images live and on-screen are a bit better due to the file compression when uploading to photobucket. There are 6 different level of magnification on the one I have, these are shown below:






As you can see it really allows you to get up close and personal with the stamp, which is very handy for inspekting certain elements of design, overprints, postmarks, perfins... the list goes on and on. What I plan on using mine for primarily is for 'flyspeking' my GB Kings, and once I get the hang of moving the stamp around under the lens I'll be really rocking. This will be way less strain on the eyes as opposed to peering through a magnifying glass.
I tested out the procedure I plan on using for 'flyspekin' with some later penny reds, looking at the plate numbers in the side bars. I was very pleased at how quick I could determine the plater number, totally impressed!
I am happy with mine, it was pretty cheap and works well for what I want it to do!
Have a Good One,

Skilo54