For your price range there are only really a few options in terms of speed and materials.
You have the FDM machines such as the makerbots/UP and others, and then you have the steriolography (I think that's how you spell it) such as the Form 1 and the new one Autodesk are producing which uses a UV laser to cure resin from a wet tank.

Each have their own pros and cons, for school work I would go with an FDM machine that can print ABS. It's still about the strongest material structurally you can print without spending a fortune. The biggest issue with FDM machines is still the parts warping and stressing as they cool, particularly on larger builds. If you want small detailed parts for show, then the Form1 style printer is great. All of them can be a pain to get used to to be able to produce good prints though.

If you want a great quality print and almost perfect everytime then the price range shoots up by over another 25k for objet machines. We have an Objet 30 which is amazing, but a little brittle for some things (and material is over £240/kg)