Microscopes

Has pictures of 2300 magnification images - http://jb.asm.org/cgi/reprint/13/4/255.pdf

Says never use the oil lense
Someone saying they couldn't resolve images with the high power lenses - http://www.opticsplanet.com/msgboard/about12395.html&highlight=oil
How a teacher grades on the curve - http://shs.westport.k12.ct.us/mjvl/lazaroff/curve.htm

For the best buy in a beginner's microscope, try the LOMO P-111.

This microscope sells for less than $100, but it has absolutely nothing in common with other microscopes in its price range. It is a Russian (not Chinese) made stripped down research grade microscope without a binocular head, mechanical stage, built-in illumination, or oil objective. However, it does have dual focusing, an iris light control like an expensive model and it uses the same high quality eyepieces and objectives as much more expensive LOMO microscopes. Best of all, it can be upgraded at a later date with illumination, mechanical stage and oil objectives - something you cannot do with microscopes costing many times this price. It is priced low only because we purchased this model in bulk from LOMO in Russia. This is easily the best buy in a beginner's microscope on the market.

40x - 2000x microscope $238 - link