For most areas of the U.S., $3.95 is charged for every day that an electronic toll is used, in addition to the actual tolls. The charge is up to $19.75 per rental period.
In the Chicago Metropolitan Area, a fee of $9.99 per rental day is charged for rentals from airport locations, and $7.99 per rental day at non-airport locations. This covers the use of the transponder and the toll fees incurred.