Anything that's "free" shouldn't be directly trusted. If a service is free, there has to be a catch somewhere. In the case of many social media platforms you're oftentimes the product as they will be selling any and all information they can gather.
There are however also other cases. Programs such as Winrar just don't try to earn money from an average user. Instead, they focus on large companies.
Whenever you use Winrar, a popular data encryption, compression, and archiving tool, after the 40 days free trial period, you'll be greeted with a reminder that Winrar is not free software.
It was purposely implemented in such a way that ignoring the message had no consequences.
In this way, Winrar gained a large user base including many companies.
The companies, in contrast to an average user, need to worry about their public image and are at risk of getting sued. They're thus extremely inclined to just pay the small fee.