Florida can be pricey in the winter. Stay inland and south of Orlando for warmer weather. One park that seemed nice when we stayed there (not in the winter) is Christmas RV Park in Christmas FL on Hwy 50 between Orlando and Titusville. www.christmasrvpark.com I would definitely make reservations.
Farther north and a bit cooler but still warm most days is Williston Crossing RV Park in Williston FL. In Florida in addition to monthly rate you usually have to pay for electric. We averaged $75 a month for electric during the winter. We conserved a bit but not drastically.