Sell blood or donate plasma. Plasma is a component of blood, and the process of extracting it is similar to donating blood: your blood is drawn, the plasma is separated, and the red blood cells are returned to your body. Laws may not technically permit you to sell your plasma, but you can be compensated for your time spent donating. In the United States, you can make about $200 a month by registering with a plasma center near you.
What’s the catch? None, really. Cash back apps act as affiliates for many online merchants, which means that whenever you make a purchase through one of the apps, they get a small commission — but then, they give you a portion of that commission as “cash back”. For example, if I buy a pair of Nike shoes through the Ebates app (or website) and spend $75, Ebates may get a $10 commission but then they’ll pass $7 back to me. It’s basically a way to get sale prices on stuff that isn’t on sale!