That’s right: free. It used to cost $25, but now it’s free. In fact, I heard a rumour that anyone who paid the $25 might actually be reimburse for their trouble. But I can’t find this information online, so perhaps…you’ll have to wait and see.
When anyone publishes their book through CreateSpace, a Print on Demand company owned by Amazon, they have the option of getting their books into stores other than Amazon. This is not the brick and mortar store but the online catalogue of these stores.
In other words, if someone wants your book, they can search the online catalogues of Chapters/Indigo or Barnes & Noble and order it. There’s other book stores as well, but those are the two I’m most familiar with.