not looking at slides, looking at metal surfaces.
I'm not a metallography expert but I don't think you need a cytology microscope for that, let alone a TEM.
Optics' prices vary dramatically depending on the manufacturer but if you're doing it for the sake of curiosity, a professional $300 optical microscope will do just fine, at least for starters.
I have a Hund Wetzlar V200 at work with 4X, 10X and 40X lenses which you could find, used, for about $200 and does the job.