If you do most things based on a cloud, I would use Deep Freeze or something similar, when you restart the computer all changes to the hard drive are discarded. Stop Deep Freeze for updates and then turn it back on.

I was put in a very similar position over the summer. The small business is now nearly bankrupt. If they can't afford software there is a major problem and it might not make sense to work there. I would explain what is going on to a boss, and request the software. If that doesn't work, leave the company and turn them in. Do your job, and don't worry about being the bad guy.