Places that offering you free bitcoins ... something smells wrong, scammy. Nothing is for free!
I got to see a few times in different companies when I bought bitcoins, the price was x and at the end of the process, I got to see their fee that wasn't included at the beginning.
Some scammers pretend to be the company and they will take your money. If you decided to buy bitcoins, at least do it with the company you want, call them, talk to them, don't it with someone
who called you, it may be a scammer.
So, if you saw or heard that you can earn bitcoins for free, search on google "buy bitcoin" or "buy bitcoin with credit card" for example and you find good and trusted companies like
coinmama.com and coinbase.