Well, then, I guess there is really a good deal of truth in "There Ain't No Such Thing as a Free Lunch" (TANSTAAFL). 
But, yeah, anything that has the word free in it, especially if we are talking about sites and offers and the like, it should be approached with utmost caution if not dismiss it altogether as an outright scam.
And to end up safe rather than sorry, it would be prudent not to chase that which is free most of the time. If not a scam, it would probably be worthless.
But of course it is not absolute. There was once a time when a faucet gives you 50BTC.
But, yeah, anything that has the word free in it, especially if we are talking about sites and offers and the like, it should be approached with utmost caution if not dismiss it altogether as an outright scam.
And to end up safe rather than sorry, it would be prudent not to chase that which is free most of the time. If not a scam, it would probably be worthless.
But of course it is not absolute. There was once a time when a faucet gives you 50BTC.