Microsoft Office is one of those products that is hard to do without.  At some point everyone needs to open or create a Word document. Power Point, Excel and others aren't quite as needed but are very nice to have.  There also aren't very many competitors to Office. So you are stuck paying $400 for Office... or are you?
Open Office is an open source version of Office. It works just about same as office, has all the same programs, and like all open source software, it's free!
    So is Open Office that great? I've been using it for a little while now and I've been completely satisfied. I should note that I haven't tested out any of the advanced features. I've mostly just created short documents and sent them to people. So if you want a review of all the programs and the advanced features, you'll have to look elsewhere. From everything that I've heard, it's a great alternative that will do what you want.
    Reasons not to get Open Office... If you already have Microsoft office or can get it for free then stick with it. If you heavily depend on MS office and you  don't  have time to learn something I wouldn't switch.

To find out more and download it click here.

PS Google has online versions of Word and Excel in the works but aren't available to everyone yet. While not Open Source, they are expected to be very nice and good alternatives to their Microsoft counterparts.