We have not taken a family vacation in about 2 years and I'm really getting stir crazy!

I am looking for a place in the South East US that my husband and I could preferable drive to and have a cheap vacation with little one (who is 14 months). I know we can afford the travel and lodging, but just not sure about all the daily activities that cost money! Looking for a 2-4 day trip even!

Any suggestions? Name the place, why its great, and cheap/free things for families to do!