Another popular site to earn money doing gigs is Amazon's Mechanical Turk. You get paid a very small amount per gig (sometimes as low as $0.05) but you can do these tasks very quickly. For example, you could be asked to identify a picture or type certain text. When I was in college, I used to do these gigs in class and earn money while taking notes.
Watch for emails asking for note-takers. Once a fellow students' needs are documented, disability services will contact the professors and ask for volunteers in the class to take notes, and your professor will in turn email the class. You can also upload your notes to a platform like Stuvia, where you can earn money by selling your notes to other classmates.