I don't think by earning it fast OP meant working in real life, he obviously wants to know something about how to earn it online.
well if that's the case , OP is looking for nothing unless he will do illegal shits like scamming and other kinds of online fraud
Yeah, they are the only ways to get bitcoins fast, but he will get more curse then the money by scamming people, and gambling is also a way for getting fast bitcoin but there is no guarantee is you will get it or not, you may get 1 btc with just a capital of 0.1 but you may even lose it in seconds.