https://en.wikipedia.org/wiki/Bitcoin_faucet

It doesn't sound viable as of 2016 ...

• Free bitcoins, given away through altruism to introduce newcomers to bitcoin ... that was possible some years ago, but it doesn't make much sense today, I believe one would get very low return for the money.
• Microtransactions aren't viable due to high transaction costs
• Some faucet operators try to earn money through advertisments, etc. Most faucet visitors would probably be better off by doing proper work for the bitcoins ... and what profit can the advertisers expect to get from customers that cannot earn money through work?