Search engine marketing is one of the cheapest ways to market your website. You are able to get results in the search engine that people click on for $0 per click.
Succeeding at at search engine marketing is about SEO. You want to optimize your site for search engines to see the best benefit possible. This means having a well designed site with a lot of links. I have found that the best way to get links is by offering a tool that people will link to. I do this with Wordpress Plugins.
What kind of tool would you like to offer?