Tracidee,
The higher toll road is Route 417 that is accessible by the south exit of the airport. There are manned toll booths along the length of the road, but when you exit, most of the booths are either for the Florida version of electronic toll paying or an exact change lane. The toll is 50 cents. I know that this lane is set up to be manned as well, but in five years, I have never seen it set up any other way except for exact change. I think as long as you have a dollar in mixeed coins, you should be alright for that exit.