I just bought a brand new scope for $17. To be precise, it is a USB endoscope or inspection camera. I do not have a particular use for it yet, other than tried to look into my ear for the 1st time in my life. It may be a useful tool when some small parts dropped in some hard to reach places.
The cheaper ones goes for about $5 each on Ebay. I picked this one because it advertised for 1280x720 resolution, Android support and 5.5mm in diameter, though the captured image does not look like with a resolution of 1280x720 and as expected, the image quality is not that good. And also the Android part did not work for me. The imager is a GenesysLogic IC(?).
The 1st picture is the camera head.
The 2nd picture is a captured image by this camera. It was taken about 2" away from the paper. 2" is about the distance having the best focus.