Born and raised in Florida this list in comprised of all my favorite cheap places to go and cheap things to do with my family.
Some places and ideas listed are just one or two hours of fun and some are all day fun!
(All prices,dates and times should be verified before visiting. Please verify with venue websites where applicable)

Blue Spring State Park
2100 W French Ave, Orange City, FL 32763

www.floridastateparks.org/park/Blue-Spring

Blue Spring State Park covers more than 2,600 acres, including the largest spring on the St. Johns River. Blue Spring is a designated Manatee Refuge and the winter home to a growing population of West Indian Manatees. There is a free self-guided tour inside The Historic Thursby house, built in 1872. There is also a playground and plenty of places to eat a picnic lunch. You may want to camp overnight as well.

Personal Recommendations:
The Manatees are so gentle and playful take lots of pictures!
Bring a picnic lunch
Take the house tour it's full of history
There is a beautiful Mosaic Manatee Sculpture perfect for a picture opp

Hours of Operation:
Open 365 Days a Year!
8:00 AM - Sundown

Cost:
$6.00 per vehicle of 2-8 people
$4.00 single person vehicle
$2.00 per pedestrian, bicyclist, extra passenger