The Florida Times-Union newspaper annually publishes Discover Jacksonville magazine. Although the cover price is stated as $4, I got mine for free at the Jax Amtrak station, so I'm sure it can be found for free at other locations listed on the website
http://www.jacksonville.com/discover/
It's full of information about the First Coast counties and cities/towns in them including median home prices and demographics (be forewarned however: the descriptions are quite upbeat and paint a little bit of a rosey picture of everywhere, leaving out some of the negatives that you can see by reading between the lines or you may need to do some additional digging.)
The magazine touches upon just about everything from government (state and local) to pet rules per county to nightlife and restaurants to top employers and growing job categories (with estimated average wages) to leisure and recreational activities.
P.S. Happily, it's not overstocked with ads either.