For the FL portion, the I-Pass (which is an EZ-Pass) will work on 417 from the airport to exit 6, International/World Drive, but not past that point. That’s the end of the Central Florida Expressway (CFX) section of 417 as you head into WDW. For many travelers, that will cover their trips between WDW and MCO. It also works on 528 from the airport east to the end by I95 if one is heading to the cruise port or Vero Beach.
The CFX Uni works throughout FL (since it is EPass compatible) as well as all of the 18 states that are EZ-Pass territory (a substantial portion of the country east of the Mississippi). You can now purchase a Uni transponder from
Amazon for $18.50 with Prime shipping (a small premium compared to the Uni price direct from CFX). See GoWithUni.com.