As above, as an addendum:
1. If you attend a post secondary institution, look into Microsoft Imagine or around its pages for software offerings. Office is often available for free or at low cost through this vector, legally.
2. See if your employer participates in the "Home Use" program. This lets you buy legal copies of Office for a steep discount (typically they will cost only $10 or $15)
3. Use an open source/free Alternative:
- Calligra
- LibreOffice (Recommended)
- Kingsoft Office
- Polaris Office
- WPS Office
- Google Docs
- Microsoft Office Online