Hi,
You asked how to earn bitcoins, that's almost impossible nowadays, you need too many machines... But it is possible to get some ethereum tokens for free when they launch (by following their twitter etc), let me know if you're interested I can recommend a page or two to you. Otherwise no choice but to buy bitcoin at an exchange!
Using machines to mine bitcoins is not the only way to earn money. That is why you're wrong about earning bitcoins is impossible. There are different ways to earn btc like joining bounty programs, selling digital goods or different goods and other ways you might think of.