Car for hire
Cars can be rented in Tehran through the newspaper (Tehran Times has advertisements) or several rental places in the city. Generally cars come with a driver so be sure to specify if you wish to drive yourself. Rental without a driver also tends to be exorbitant. Most rental places will keep your passport and/or ticket while the car is in your possession and do not accept credit card payments.
http://www.irpedia.com/iran-travel/car-rentals/