We don’t recommend a free Facebook spying tool. That’s because free apps tend to be littered with viruses, spyware, and other things you don’t want on your Mac, PC, or phone (and on their device too). Instead, it’s much better to pay for a spy app for Facebook. While it will cost you a bit to monitor their Facebook activity, when you choose a subscription-based Facebook tracker app, you can take comfort knowing that you’re choosing something you can trust to keep your information safe.