Your first means of promotion is sharing: you give your story (or copies of it) to personal friends and family who hopefully read it, like it and tell others about it.  While this can be a good way to find out how well your story will be receied by others, it's quite limited.

    The next step up is to announce and offer your story on social media such as Facebook and Twitter and book sites like .  These can be used for free and broaden your reach, but your message can be lost among all the other thousands of posts that people put up daily and there's no guarantee that your posts will reach everyone you expect them to.  And it can be a lot of work building friends lists and followers this way.

    Another way to get more exposure is to publish with Lulu, Amazon, or another self-publishing company.  This at least gets your book listed on their website, and often other sites as well, but again, how does anyone find it?  Your social posts can point to the place on these sites where your story/book is, but as stated above, that's also limited.

    Thus most succcessful authors resort to paid advertising to get started.  For the budget conscious, Facebook can "boost your post" (make sure at least x thousand people have it on their timelines) for as little as $5.00, and will list your book for free and send 25 tweets of your choice to 51,000+ book followers for $15.  Even so, your ad must have something to set it apart from the rest of the hopeful authors out there, and it's a numbers game: the more you spend, the more people see your ads, the better known you become and the more books you can sell.