Any Ways to Get a Cheaper OS?

Hey everyone, 

Just curious if there are any legal ways to get an OS like windows 7 or 8 for cheaper than what they are listed for on some of the major retailer sites. I am a university student in Canada and my school used to offer cheaper OS's for students... but not anymore. Any suggestions? Thanks in advance.

ask around school to get set up with microsoft dreamspark, free software for students if the people in charge aren't pricks

Awesome thanks.