Bitcoin faucets are sites that purport to help users earn bitcoins "for free" but often fail to deliver or pay such paltry sums as to make the effort itself pointless.. They usually needs address entry and captcha filling. You can revisit faucets every given time to get more.
The first faucet was operated by Gavin Andresen, however it has not functioned since Jan 30 2013.
For Testnet there exist different faucets which give out coins for people who want to do tests on the Testnet3.