I lived for next to nothing and I had a gig maintaining a system that paid something like 1500 euros a month and it required few hours a month. Did that gig for 12 years, saved me many times when I tried to launch other projects.
It was custom SW created by construction company: things like quotations, warehouse management, controlling, some accounting integrations, time tracking and what not. At the end it was sold to about 60 other companies. It was about 30 years old when the development stopped: it was slowly being eaten by more modern software, but I am sure it is still used somewhere. I was single dev working on it since my day 1.
