Last year we had a car out of Ft Lauderdale. As far as I know, all hire cars come with an electronic pass (EZ pass or similar) which is attached to the windscreen by the rear view mirror. You can switch it off if you know you are going on non toll roads...just to be on the safe side. However, you need it on to go on toll roads. The charges are listed on your car hire website/booking form. I think it is usually about $3.50/day (whether you use it once or 100 times), up to a maximum of $16 for the hire period. So, once you use it on Tuesday(say), you can use it for the whole of Tuesday for $3.50. On Wednesday, if you don't use it, you don't get charged. If you then use it Thurs,Fri and Sat you will hit the $16 and can use it as much as you like with no further charge. Does that all make sense!?