There are many things you can do to advertise in a limited budget. The less dollars you are willing to use, the more time you have to be willing to put into your own advertising. Here are a list of some things:

1) Post relevant comments on other people's blogs.
If you do this, you should post comments that are meaningful and relevant to the post you are commenting on. Don't place a post that is an advertisement, but place a post that leaves people wanting to know more, and that will cause them to click on the link to go to your website. If you post a blatant advertisement, chances are, your comment will never make it to your web site.

2) Make relevant posts in related forums.
The more posts you make in forums, the more traffic you can send to your website and the more you can expose your product. As in the case with commenting on blogs, blatant advertising is not welcome. If your posts are informative and compelling, you can get people who read your posts to go to your web site

3) Post articles to article directories and other web sites.
Writing quality and informative articles and posting them to article directories will send traffic to your website if you create a compelling resource box. The article should be written so that it is informative, but lets the reader know that they can find more information on the subject at your web site. The higher the quality of your article, the more places it will be placed online. People are looking for quality content and will use your articles on their web sites and in their newsletters (with credit given back to you of course)

4)Submit your articles to ezines with high circulation.
You can go to ezine directories and find ezine publications that are relevant and accept article submissions from other authors. You can then submit a quality article to that ezine publisher. If they publish it, you will get great exposure for your product or service and you will get customers and traffic to your web site.