PSA: One of the coolest, free services on the Internet today is one that many people would benefit from, but it seems almost nobody knows about it...
Microsoft has made completely free, web-based versions of Word, Excel, PowerPoint, and OneNote available through its (also free) SkyDrive service. These are reduced-functionality versions of the desktop apps, but they are still extremely functional, and you probably wouldn't miss any of the omitted features. It works on all of the major browsers, including even the iPad. And, like Google Docs, they support real-time collaboration so multiple people can be working on the same file at once.
To access this software, just create a new (or activate an existing) SkyDrive account at www.skydrive.com. Click the "Create" link at the top of the page and select the type of document you want to create. Or upload existing files from your computer and view/edit them online.
These aren't time-limited trial versions of a paid product... they are completely free to use. And if you have 2010 or 2013 versions of the desktop apps, saving and opening documents directly to/from SkyDrive is built in. (And working on documents saved to SkyDrive also enables real-time collaboration in the desktop apps as well, without a SharePoint server.)