Here are some suggested ways you can promote your website that will cost you nothing.
Identify a handful of other blogs in your niche (or surrounding niches) to offer to write some guest posts for. There’s no better form of advertising, free or otherwise than writing articles. You could also write and submit articles to article directories like EzineArticles.com or GoArticles.com.
Pick 5 top-100 blogs in your niche. Read their articles and write interesting and constructive comments that contribute to the conversation on relevant posts.
Spend time networking with other bloggers – emailing them or chatting on IM and exploring ways of working together in win-win ways. You could promote the content of other people and as you help them achieve their goals, the benefits will eventually come back to you.
Spend time reading every Digg top story for that day and get familiar with what makes for a good Digg story. Then spend some time finding and submitting great articles to Digg. You could also contact every blogger you know, and ask them to give you a heads-up when they had a special article coming out. That way you could Digg those articles before anyone else.
Use a variety of content sharing sites, social networking and community based sites. Build power user profiles for the biggest social media sites like Digg, Reddit and Stumbleupon.