Well, when i was new in bitcoin field, than always i spend my time to search the free bitcoin sites. But i learn from my experience nothing any sites here where we earn free bitcoin, except faucets but they pay very low and in this way, we can't earn 1 bitcoin, except gambling is only way where we earn fast but on the risk. So i choose different ways like hold the bitcoin and also i try to do altcoin trading.
if from free you mean without investing money. then signature campaign is the best option, where one can make bitcoin for free. one can also earn bitcoin for free without investing money if he has good skill of designing.
Agreed signature campaign can be treated as an free earning of bitcoin as you are not going to invest any capital in it and you will get paid for the posts that you make on weekly basis, and I think many people are making good amount of bitcoins by working on signature campaigns.