I am preparing my book for print-on-demand through Amazon's CreateSpace service, and I am trying to understand the options for getting an ISBN.
I am a little confused. CreateSpace offers a "free" ISBN, and calls it an "ISBN", but says "This ISBN can only be used with the CreateSpace Independent Publishing Platform." So... it's not really an ISBN, it's just an internal version of an ISBN that only works within Amazon's services?
It seems that buying an ISBN elsewhere, even though I've read hints here and there that it is possible to do it for cheap or free, seems to cost around 125 US$, or the equivalent in other currencies (I've looked at Canadian and UK options). That CreateSpace is offering me one for free does seem appealing.
Is this ISBN offered by CreateSpace a real ISBN or not?
And this is my main question: If I go with CreateSpace's free ISBN now, and then later I the opportunity comes up (or I just decide) to make my book available through distribution channels, can I then buy a "regular" ISBN and go with that? Would I need to?
(Please note that I am not American, and a lot of what I've read on the internet is very focused on options available for people in the US, which makes me even less certain of my options.)