IBM research has released a project that allows you to build a motorized, high quality microscope from Lego bricks and a Raspberry pi for roughl $300. They call the project MicroscopPy, and they’ve shared the build notes on Github.
As you can see in the video, the build is surprisingly simple and uses the standard Raspberry Pi camera to get some pretty impressive results. On top of being able to do some nice automated microscopy, it can also be set to do macro photography, which is a big bonus when documenting your projects.
Admittedly, some parts were 3D printed instead of buying the more expensive Lego counter parts. However, the author does share these parts as well, so you can 3Dprint your own.