
This is from Becky Flansburg, author of Sissy Goes Tiny:

“You can buy one (or 10) ISBNs from Bowkers (www.myidentifiers.org) and they are 100% yours. Buying 10 enables you to have 10 in a sequential series (helpful if you intend to be a publisher or write more books). BUT, there is another option too: when you upload your book to Amazon, you can choose to get a free ISBN through them. The downside is that Amazon owns your ISBN number, not you. If you use Amazon KDP’s free ISBN, they will be listed as your “publisher.” So, if you have a business set up and want your business to be noted as your “publisher,” then buy an ISBN from Bowker.
If you would like to sell your book online in places other than Amazon, you will need to buy your own ISBN. Using Amazon’s free ISBN is their way of making sure you can only sell online through them. Which is really not a big deal. FYI: only 25% of book sales come from “non-Amazon “ sites so it’s fine if you only want to sell online via Amazon.
Amazon may take a chunk of your profits, but selling through them puts your book in front of MILLIONS of potential buyers. You can ramp up your chances of book sales by using Amazon Ads and, if done right, they are effective.”
I made the mistake of using Amazon’s Kindle Direct Publishing (KDP) FREE ISBN number and now, as a result, I can not pay Amazon to run my ads. Literally, if I say that I am willing to spend $5 a day for a month, Amazon will spend $1.20 all month. And that means that Changing The Game never comes up as a recommended book. Perhaps if I get more than 50 positive reviews, that will change. I will keep you posted.