@ Cathy Markland state parks used to be cheaper, but many areas now in North Florida and south Georgia offer better facilities at a better rate than the state parks. And to ad to Cathy's answer below state parks are NOT the lowest. The lowest prices usually are National parks.
If you kyack (or boat)...there are awsome little islands all up the Treasure Coast with free camping. I read a couple years ago there was free camping in the Savannah's but i just again started looking. Ill post here if I find that website
State parks are not free but are the lowest price you will get.
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