CreateSpace and Blurb are two of many companies offering free ISBN numbers for writers to publish books. Before choosing to publish your work using a free ISBN, consider your options. CreateSpace offers four different ISBN products, each with its own rules and restrictions regarding imprints and distribution.
If you have decided that you need an ISBN because your book is not simply a private work, an ISBN directly from Bowker, the official ISBN agency in the United States, costs up to $125 per ISBN as of 2015. If you are a book publisher, or you plan on having many versions or editions of your book and want to keep full control, this is the best option. If, on the other hand, you are just starting out and money is an issue, a free ISBN may be for you.
CreateSpace, an Amazon company, helps writers create, publish and distribute their work. They offer a free ISBN, a Custom ISBN, a Universal Custom ISBN or bring-your-own ISBN services. Although you may opt to start with a free ISBN with its limitations, nothing prevents you from choosing a higher service level or getting your own ISBN at a later date.