Of course, any Canadian eReader will work just fine in Florida with respect to any ebooks that have been loaded on it before one leaves Canada.
We have a Kobo eReader and have used it in Florida for a number of years. We usually load up all our ebooks before we go but we can still purchase additional ebooks from the Canadian Chapters/Indigo site (redirects to Kobo for actual purchase) while in Florida negating the need for a USA address and credit card.
And also, as has been mentioned, there are tons of free ebooks.
Calibre is a great program to use to manage one's ebooks.