Unfortunately, I can't answer your question. I do rent a lot of cars here in Florida because I don't own one of my own any longer. But, I always plan my routes to avoid tolls. Although, avoiding tolls out of the Orlando International Airport requires pre-planning. (You can't simply follow the signs, as they all lead to toll roads.)
I'd recommend visiting the Transportation forum. I'm guessing you will find better answers over there.
Transportation Forum:
http://www.disboards.com/forums/transportation.16/