There's lots of free advertisement available online. You can spend endless hours signing guest books, registering at this site and that site, joining directories that promises thousands of hits, link to this blog and link to that blog and all for free. However, after 10 or 20 hours of doing this, what have you accomplished. Truth is even if people come to your site or blog, your site and the content is what keeps them there.
My suggestion is that before you start linking your blog to other blogs and going through the process of the above. First, create some great content on your blog for you're visitors to read. Make sure that you have your blog filled with content and then consider marketing, advertising or sharing you're blog.
While I would definitely take advantage of free advertising, marketing, links exchanges, and all those goodies. If you are offering products or services, I encourage you to also have a marketing plan that includes paid ads that targets specific areas online.
The bottom line is this. If you are trying to sell a product or a services, you are going to have to spend money to advertise those products and services.