Hi
Andrew_Levenson,
In addition to the great advice you have already been given you may want to check out your local
FreeCycle group (you can also post a 'Wanted' ad asking for equipment you are interested in). My younger sister managed to get a nice G4 Mac (sans hard drive). Since you are young adults (note this is
not supposed to sound patronising), if you are going to someone’s house to pick something up, make sure you always take an adult along. There is also
DIY Parts, which may offer items you want in your area, or for the cost of shipping.
Hope this helps.
Martin