When u use the word "Bitcoin", do you just mean Bitcoin or any other cryptocurrency too?
Because earning the real Bitcoin can be a rough start while investing in some small altcoins can give much more profit when starting with small investments.
Take a look at
http://www.coinmarketcap.com, here you can find all altcoins and tokens that are registered. You can find a link to their website and see what exchange they can be traded on.
You can go and buy some cheap altcoins and just let them sit in a wallet while hopefully they increase in value
You can search for platforms to invest in lending contracts like Bitconnect, Octoin, Lendconnect. Can make you some good profit.
And you can invest a few thousand hard earn dollars/euros to get a mining computer and mine your own bitcoins/altcoins.
Need some more advice just gimme a PM =)
Good luck in making Bitcoins!