Microsoft rarely gives away software. When they do, it is to drive future sales (student, developer, and 3rd world versions), or it is because you already paid for it.
It is possible to run Windows Vista and Microsoft Office for free for short periods of time - by using the trial modes built into each.
When installing Windows Vista (any Vista DVD will work), simply
leave the product-key field blank when installing. You can then pick a version (Basic, Business, Ultimate, etc) to install. Windows Vista will work for 14 days before it will demand a key and activation. (At which point you can just format and reinstall to start another trial period)
Microsoft Office 2007 can be downloaded as a
60-day free trial.
If you need a free OS and office suite that isn't time-bombed, I recommend
Ubuntu Linux. Its quite user friendly and includes OpenOffice.org. (I know it isn't Windows, but it fits your budget)
Hope this was helpful!