Looking at the map, you would have some tolls. If you take I-4, you might have a small amount to use 417 to get to I-4. There might be a way to avoid the tolls with the side streets. 25th Street or Lake Mary Blvd look like they go straight over to I-4.
If you take 417 south around Orlando (and the traffic) and past MCO to get to WDW, there would be quite a bit more in tolls. Not sure how much they will be, though.