A lead magnet is basically a piece of content that you give away for for free to potential customers, in order to capture their attention and convince them to hand over their contact information. Most people aren’t going to sign up to your mailing list just for the sake of it, so a lead magnet allows you to ask for something in exchange for something your audience finds valuable.
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!