When I was a teenager, my main source of income was online Usability testing. It was pretty inconsistent, some weeks were 10$, some were 60$, but it took fairly little effort and time. All I had to do was click through a website and narrate how my experience with it was.

It probably pays way less nowadays, but I remember that usertesting.com was my main website for this back in the day because they paid 10$ per test (even if it’s just 10min) and had plenty of opportunities. If you want to try it, make sure to state your household income/education level/job is a bit more than it actually is. You do get more tests that way