This site is definitely worth a look if you are looking to purchase Office or Windows 7. There are restrictions on eligibilty but if I am correct as long as you are a student or the parent of a student you are entitled to purchase the software ' for the use of the student' :)
I have already purchased both Microsoft Office and Windows 7 Upgrade.
Can't beat it IMHO.
Apparently the deal ends soon (was supposed to finish end of October but has been extended)