There is reason, you know ...
... why I tend to refer to a specific form of parastic life as "marketurds".
As others have pointed out, if it seems too good to be true ... well, then, it is not true.
Also, remind ourselves that if there is any kind of condition attached to an offer, it is not free.
"Buy One Get One Free" is not free. It's a half price offer. It would only be free if it were "Just come and collect it, leave without paying". And even then, if it were "Just come and collect it, leave without paying after supplying your email address", it wouldn't be free: you had to surrender something of value; a condition had to be met.
Not only was Mr Heinlein correct (TANSTAAFL), the world's most widespread technological phenomenon is founded upon a lie: neither Google nor Facebook nor Twitter are free, because you surrender something of value to prying, lying manipulators.
It is really quite astonishing how utterly stupid so many people can be. But that's what pays the marketurds' bills, and keeps them from rummaging in wastebins (assuming, on the evidence, that they have no beneficial skills).