My parents had a trailer in Holiday, FL (About 45mins north of Tampa)... Monthly fees I think for their place were around $300 a month.. Fantastic fishing as well, my oldman and I would go out to HoneyMoon Island State Park and catch all kinds of fish (whitings, pomps, sea trout, ladyfish, spanish mackerel, etc).. Also if you like baseball, Dunedin is the place the Jays call home for the winter.
They also checked out Panama city last year.. The accommodations were great, but the fishing was less then par...nice beaches though, lol...