Not along the coasts, those are expensive and if they're less expensive they are already booked. Try inland if you want "budget-friendly FHU". Try warm and south of I-4.
Sebring: Whispering Pines Village. $460/month+ele - 1 month. 2 months $410/month+ele. $395/month+ele. for 3 months. We stayed there 2 years ago for a couple of nights. Nice folks run it and the residents were friendly. A mobile home section and a separate RV section. Was a bit tight to get into site, but cement patios.
http://whisperingpinesflorida.com/Melbourne: Wickham Park Campground. A Brevard County park with FHU. 390 acres county park with plenty of campsites and it's not far from the beaches. Monthly rate is $534+tax. We will be there for a couple of nights next month while visiting friends in the area. Have driven through and it has large sites and is camper friendly.
http://www.brevardcounty.us/ParksRecreation/Campgrounds/Wickham/Home#Winter Haven: Cypress Campground & RV Park. Stayed there 2 years ago for a few days. Monthly rates $595 for a back-in & $695 for pull-thru. Inland, but close enough to Orlando and not far from I-4 if you want to drive to either coast.
http://www.cypresscampground.com/Crystal River: Rock Crusher Canyon RV Park. $675/month-includes elec., FHU, and very good cable. We've stayed here quite a bit and will be here for 2+ months starting mid-January. Like a state park with all the trees. Crystal River isn't exactly a beachy area, it's called the Nature Coast. You can get to the water, but mostly good for fishing, kayaking, and eating good seafood.
http://rockcrusherrvpark.com/
