I think what you’re asking is how you can make extra money to pay your real estate taxes. If that’s the case, it depends on your current financial situation, the amount of your estate taxes, your skills, and more. If you visit the “Make Money” section of our website, we have a few articles with different ideas that may be helpful for your situation: https://www.dollarsprout.com/category/make-money/
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!