No, no, no! Don't go for gambling. Yes it is fast but definitely the percentage of winning there is only low. And it depends on how much is going to be your capital.
It is better to do it the usual way as others are suggesting.
Signature campaign is not really fast but the returns are assured so if you don't want to take any risks in earning bitcoin then signature campaign is the best method.
Yes signature campaign is not fast at all. And you should not really rely on it. And there is no such thing as free earnings with bitcoin.
But fast there is.
But for having them both fast and free there is no way at all.
If you are looking for a fast and you have some skills in demand, Selling service would be the best for you because it's one of the very fast to earn bitcoin.