- parking fee of the rental agency parking lot.
child car seat rental - the law various from country to country, but if a child car seat is needed/wanted there could be an additional charge per child car seat.
gas charges - you should return the gas tank full, or you could have to pay additional fees, plus the cost of gas at a higher price then you would at a local gas station.
drop-off charges - one way rentals - there could be "drop off charges" if you drop the car at a different location, then where you picked up the car.
24 - hour clock - late fees - most company's rent 