I know very few people who have paid for excel specifically. everyone pays for MS office, albeit because it includes excel, but in an workplace setting the main thing you're paying for is outlook/exchange the fact that word/excel/powerpoint are bundled is a plus.

The main point I'm making is that no one has to go to their manager and justify paying for it. It's already bought and paid for, and because of its ubiquity most people have a pretty good idea of how to use it.