You can earn bitcoins through several ways. However, I don't think any of them can be classified as free. Nor can they be classified as fast at the same time. They all require lots of your time which is also an asset, or they just pay way too less.
Browsing through faucets, signature campaigns, doing tasks, offering services, doing offers, they are all free. Although they take up a lot of your time, for little reward.
Browsing in faucets are literally fast and free but you will know in the long run that the amount you can earn with it is very little.
That's why you must need to have other source and all the things you have said are right.