I fail to understand why you need a $500 laptop for school.
Presumably if you don't need it to play games, then you probably won't be doing anything processor or graphically intensive.
I come to the conclusion that all you'll be doing is everyday work such as writing documents and compiling data in excel, which can be achieved pretty well by a standard generic $200-300 laptop with Ubuntu (unless your school requires you to run some sort of windows-only program which cannot be run under Wine).
And if you do not have a laptop by the start of school I don't see what the teachers could possibly do to you, so I would worry about much apart from being behind on work (In which case you can just do the work on your home PC or with another friend who has a laptop, presuming you have a friend in the first place(not saying you don't or anything)).
Lastly, what's with buying a new laptop every year? Do you like consistently break them? From what I understood, you mentioned something about giving them in... But I somehow don't believe that.