If you want to do spectroscopy without resorting to hundreds of dollars, you can do spectroscopy with a webcam and a diffraction grating...
http://www.iceinspace.com.au/forum/s...ad.php?t=70573
http://www.patonhawksley.co.uk/staranalyser.html
and for analysing the data you capture, you can use programs such as this...
http://www.rspec-astro.com/
Public schools should be able to afford equipment like this without breaking the bank.
The dearest part is if you want to purchase a scope. But even there if you shop wisely, you can get a good scope for a good price.