How do I promote my website(s) for free or very low cost?

You will never succeed just for thinking how to promote websites for very low cost, cause its just so many of them are here on the internet..IF you want to promote your website for very low cost, first of all it depends about what is your website..and how much knowledge do you have about websites promotion you know what I mean? As more knowledge you know how to do that as less expensive it is..

One of the best thing you can do if your serious about promoting your business is to first get a real domain name. Most people and search engines don't give these sites any weight. Spend a few bucks and get a real site then start promoting your sites through search engine submission and link swapping.

write some free articles and give it to article directory.

I use webrings to promote some of my sites. and then after a while they get into the search engines, so more people come.