Microsoft Word is a program used almost universally by people both at work and home for creating documents on their PC. If you use a different program, you might have found you cannot share documents with other people because they are not compatible. Word can be expensive to purchase depending on your budget. Fortunately, you have some options.
You can use an online version of Microsoft Office for free. Similar to Google Docs, Microsoft Office Web Apps are online versions of Word, Excel, and PowerPoint that you can access just by having a Windows Live ID. These programs are not quite as full-featured as the version you install to your PC via an installation disc, but they let you work with Office in a web browser.
If you want to try the full version of Microsoft Word, and only need it for a short time, you can download a free trial from the Microsoft website. Unfortunately, this is a limited trial and access will typically run out after 30 days.
If you only need to read other people's documents, you can install the Microsoft Word Viewer on your computer. This is a free download that allows you to view Word documents. However, you may not edit documents or create new ones.
If you purchase a used computer, it's possible to get a copy of Office included in the purchase. Sometimes people who sell used computers offer to include programs like Word on the computer as an added selling point.
This isn't free, but you can get the Student edition of Microsoft Word at a significant discount compared to the full version sold for home or business. You might also want to check with your school; sometimes, universities give students a copy of Microsoft Office for use with classes.