Another option is Office 2013 which definitely works with 8.1 and is a one-time fee. Or LibreOffice is another option. MS Office is better, but it's pretty easy to forgive a lot of shortcomings when something's free. For that matter, WordPad is probably more of a word processor than most people need and then there's also Google Docs which is at least usable in a pinch for a spreadsheet or presentation software. I pity people who have to use it on a regular basis because their company signed up for Google Apps, but if you just need to type the occasional letter or do a simple spreadsheet, it's functional.
I still think MS is missing out on a golden opportunity of selling access to Office 365 on much shorter time scales. Maybe someone only needs it for an hour or a day or week or a great one would be for a college semester or school year (K-12 or College). On a per hour basis the year would always be the best deal, but there are probably plenty of people who would be willing to pay a bit more per hour to only have to pay for a month or semester's worth.