And its also the fact there is no methods to do this without any risks.
How an investment site can double your bitcoin in 24 hours or in hundred hours. They will run away with your investment in couple of days once their target of amount is achieved.
That is simply impossible to double coins in 24 hours and if that was the scenario then every one would be super rich and no body would wasting their time in signature campaign.
to sum up, there is no safe method that would allow you to make easy money, get over it, you will either not make free money or you will have to risk the money you already have