Okay, so ALL publishing avenues require authors to promote themselves unless they are extremely well-established. An author in India who has self-published asked how to promote his new book. Here are five hints/tips I gave him (that are very popular) that won't cost you anything:
#1 - Web site. You really need to have some sort of a web site, even a free one, with a link or a way to purchase your book. A short biography is always a nice thing to have there.
#2 - Social Networking. Facebook, Twitter, MySpace, etc. - and they all should have a link to your web page and/or to a way to purchase your book.
#3 - Blogs. If you don't have at least one blog already, get one. Yet again, make sure they have a link to your web page and/or a way to purchase your book. If you are a non-fiction author, I strongly recommend blogging as much as possible to establish yourself as an "expert" in that field.
#4 - Newsletter. Gather email addresses at book-signing events and through a simple form you can make on your web site. Email your upcoming schedule, news about any awards, reviews or press coverage, etc. Sending it out once a quarter should be sufficient. Again, include links to your web site.
#5 - Press Releases. Make sure you write up a grabbing press release announcing the availability of your new book. Also write one if your book wins an award, or gets a movie deal. Email your press release to local papers and/or papers with interest in the story (if your book takes place in Minnesota, but you live in Florida - send the release to papers in both places). There are free press-release distribution services on-line you should also use. Don't forget to post the releases on your blog, and provide a link to that release through your newsletter, social networking pages and anywhere else you can find that's appropriate.
Of course, book signings in book stores and other venues are very important. But the 5 items above don't require carrying books around, the cost of travel, etc., and if you are a struggling writer, that makes a difference. Other self-promotion tactics may vary depending on the subject of your book.