Here is a link that will tell you more about open office. There is no need to pay for it on ebay unless you need to have it sent to you on a CD. If you have a broadband Internet connection you can download it from the website I listed above. Open office in not Microsoft Office, but it does many of the same things and possibly a bit more. You can also look at
Google Documents. It is an online office package that does many of the same things that Microsoft Word and Excel do.
Both of these items are free. If you are not aware of this and have a student in the family, you are eligible to purchase, at least in the US, Microsoft Office for students. It includes all of the features of Office, but at a discounted price of $129.