Niceol via eBay offers the 1,000x 2-Megapixel USB Digital Microscope for $14.97 plus 69 cents for shipping. That's $16 under our mention of a similar microscope from March and the lowest total price we've seen for such a model. (It's the best deal today by $5, excluding other eBay vendors.) It supports 50x to 1,000x magnification and USB so you can view the output on a computer monitor.
Note: It ships from China and may take up to four weeks for delivery.