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If you happen to work for a company that has a Microsoft Enterprise Agreement (EA) then you should have access to their Home Use Program (HUP) that gets you access to MS products for VERY cheap. Thinks like Office for $20, etc. I'm not sure if Win 7 is part of the program and what the price looks like on it but it's worth asking your IT department if they do have an EA. If you're a student MS also has decent deals through their EDU program.
 
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