Have a look at the answer I gave here:
http://www.theanswerb...e/Question786004.html
I've recommended Brunel Microscopes for many years. The Wedmore SP series are robust models well suited to a student as he'll need both course and fine focus controls.
http://www.brunelmicr...udent-microscope.html
The SP27 shown on the same page is also excellent and has the advantage of a rotating monocular head which is standard in most schools nowadays. It also has it's own illumination source. It's over your budget slightly but it's an improvement on the Wedmore series.
I've tried out the Wedmore and SP27 myself and I can vouch for their quality - my university has around 120 of the SP27 in various undergraduate laboratories the last time I checked the inventory.
If you need any assistance, give Brunel a ring - you'll find their technical advisor's very helpful and down-to-earth. Post again if I can assist further.