"What microscope do you recommend?"
Start with Craiglist and if no luck...
Call your local health clinic and see if they have any they are looking to part with...
Check out this link:
These are specific SOIL MICROSCOPES that Dr. Ingham herself outfitted, for seeing exactly what we want and NEED to see in the soil. Any of them will do however I do recommend purchasing one with a built in camera! That way we can share our organism pictures seamlessly, for the purpose of honing our identification skills-which is crucial.
All we need is 400 total magnification, so even that scope you picked up at your neighborhood garage sale should do!
Let's put the power back into our own hands and assure soil health.