As a young adult, we often try to focus on increasing our income as much as we can. Students with part-time jobs don't earn very much, so it's important to find alternate sources of income. Passive income from dividends and interest don't amount to very much unless you already have a lot of money and alternate sources of income generally amount to other part-time jobs. However, especially for college students, research labs provide an excellent opportunity to make a little money on the side by simply giving some time to fill out surveys or participate in simple experiments.
I have easy access to my university's research programs to participate in psychological or behavioral studies and earn money. They are generally quite lucrative and only take up a small amount of time. There are programs for our business school, psychology department, and cognitive science department. Each one pays roughly $10 per hour and I usually sign up for one every week or every other week. For the cognitive science labs, I generally avoid any labs requiring fMRIs or other brain scanning activities. Most of the labs I take generally only require answering questionnaires or giving my opinion or participating in some type of decision making activity. A few times, I've had to do some kind of performance like sing a song or play a video game. A lot of these labs also pay bonuses to incentivize participants so payouts are generally more than $10/hour.
Recently, I have also tried looking at online surveys. They seem to be fairly reputable but I haven't done enough to actually redeem any money for any of them. The sites include SurveySavvy, MySurvey, Harris Poll, and American Consumer Opinion Panel. Most of them pay out in points which you can redeem every once in a while, but they are definitely much less lucrative than the in person labs I do for my school. This is probably due to the ease of doing them at home and the risk of someone just automating their responses. I haven't calculated the exact pay rate per hour with these sites, but they seem to not be worth the time so I have recently stopped trying to participate in them.
I think it's generally hard to identify good research labs that pay normal participants a decent amount of money. Being at a university makes it much easier to sign up for these types of labs and they definitely help. Over the past 3 years, I've made about $900 for 81 sessions at the research program for my university's business school. It isn't a significantly large amount over 3 years, but considering the alternative of probably wasting my time online, I think these in-person labs are well worth it.