Today there are so many ways to make your dream of publishing come true without breaking the bank.  CreateSpace, Bookbaby, Lulu, and IngramSpark are the major players in today's affordable and POD (print on demand) publishers.  CreateSpace and Lulu offer no upfront fees for publishing and a pay per print option which is great for making your book a reality.  And Bookbaby and IngramSpark offer more options, such as hard cover and formatting included in their pricing, yet still at a low cost.  Amazing that within the last 10 years we've gone from sitting and waiting for an acceptance, and unfortunately more often a rejection, to immediate publication for anyone with the computer skills to send an email!  But as with anything that seems too good to be true, it usually is. 
Ease of publishing and the promise of sales on Amazon have led to an oversaturation of self published authors.  And quite frankly, a lot of crappy books.  Since you don't need to have your book professionally edited, beta read, or even proof read, you can pretty much upload a formatted PDF of gibberish, use a free ISBN, and have your name and book for sale on Amazon, BAM.com, and BN.com in under 48 hours!  Now if you are a serious writer and have taken all the proper steps to create an exquisitely written, well edited, and highly received story that you are self publishing through the same main stream POD or self publishing giants, you're now on the virtual shelf right next to the Art of Gibberish published immediately before you.  So how do you differentiate yourself?  How do you get on library shelves and the shelves of those big book retailers (what's left of them)?  That's actually very simple.  Do your research!
Every retailer from Wal-Mart to Barnes and Noble, and each public library system in the country has a link on their websites on "how to sell" your book or product to them.  Is that a lot of reading and research?  YES!  But if you are an author and worthy of big exposure, then you'd better already be used to doing a lot of reading and research. 
So now we come to the part where you're scratching your head and saying "so what does the title of this post have to do with anything?".  Well my friends I'll tell you a little secret that will give you a short cut through the quagmire of conditions that each and every retailer, and library require to get your space on their shelves; A free ISBN provided by the printing publisher of a POD service will not be accepted for standard retail and library applications to carry your title.   An ISBN (International Standard Book Number) is used by all retailers, libraries, and schools to locate and order your books.  That number identifies your book by it's publisher, author, type,