If you want a great office suite but don't want to pay a penny, try the just-released LibreOffice 5.0. It's better and faster than previous versions, and a budget-hunter's dream.
I'm a long-time user of LibreOffice, on Windows, the Mac and Linux, although haven't given it a try on Android. (I use Microsoft Office as well.) So when the newest version was released, I immediately downloaded it and started using it. (Get it here.) I wasn't disappointed.
On the surface, all looks unchanged. It's essentially the same interface, which admittedly has a bit of a dated, retro look to it. But those who hate the Microsoft Office ribbon will be pleased, because there's no ribbon in sight.
The real changes are under the hood. The biggest change is that it's just plain faster. Files open and save more quickly. I particularly noticed the speed change when opening PDFs.
Calc offers better compatibility with Excel spreadsheets, and has a number of new functions. I'm not a big spreadsheet jockey, so haven't been able to put it through complex paces. Steven J. Vaughan-Nichols points out that it isn't yet compatible with all of Excel's formulas.
Those who work with other people who use Word documents --- in other words, pretty much the entire world --- will be pleased to learn that it's better at working with Word docs, and preserves more formatting features.
There are more changes as well. For a full list of new features, head here.
If you've thought that there are no free alternatives to Microsoft Office, it'll be well worth the download. And if you're an existing LibreOffice user, you'll want to get the latest version right now.