What methods you use to make extra money online?

I prefer to use free methods to make money online.  For example, Google Adsense, online surveys and affiliate programs.  Because I would like to minimaze the cost.

I search free stuff on internet to increase the traffic to my website. Using social networking sites has impressive result. Facebook is a great tool to get traffic. But provided that the content of the website is useful for the audience.

Later I share more my ways to get traffic.

What is your ways?