Hi Guys!
We have been bopping around Florida for years. Winters are tough as every one from the Midwest and Canada want to come to Florida for the winter. So, it's supply and demand! The parks can charge $600 - $1800/mo, depending on locale of course. They only have six months to make their money because no one wants to be here in the summer. We are currently paying $334/mo plus electric. That rate goes to nearly $700 when the snowbirds arrive. And this is an old park with mostly park models and very tight roads. We are around the Tampa area right now.
Certainly up in northern Florida it can be cheaper, but if you are any where near the water it's about the same as the rest of Florida. We have found the inland parks down the middle of the state to be fairly reasonable. If you don't care about being near the beach, the RV spaces are bigger and the rates are definitely cheaper.
We stayed at a park in Arcadia that was very nice: Cross Creek RV Resort. It is in the middle of orange groves. It is very peaceful if that is what you are looking for. It's a cute little town with everything you need. If not, Sarasota is directly west.
We use Woodalls.com to research parks as well as rvparkreviews.com to find places we want to try out. Google Maps satellite views also helps in checking out an area. Then a phone call can also help to sometimes find a better rate. Some campgrounds are not real good at keeping their website rates up to date.
The other thing you can do, if you can find a job, is to work camp. For 12 - 15 hours a week for each of you pays for your site. Some want additional hours, but you can pick nicer parks that way. Workamper.com is a good source for this kind of research.
Happy Hunting!