title_body: How do I get an ISBN?
upvoted_answer: The national official bodies that you mention are the only ways to get an ISBN in your name for your manuscript. If you go through, say, Smashwords to get your ISBN, then Smashwords will be on file at the ISBN agency as the publisher of the manuscript. When you get an ISBN from anywhere else, they are basically buying them from Bowker (or whoever) in bulk and reselling them for a markup. Here's some further info: https://savvybookwriters.wordpress.com/2012/06/08/author-beware-unauthorized-resellers-of-isbns/