Cheap car rental in Jo'Burg?????

Three of us are coming to Jo'Burg on March 17th. We will be waiting a day or two for the bikes to show up and getting them ready to ride -- we are heading up Africa to ?Egypt?, if there is still an Egypt when we get there. But, we will need to rent a car to get around Jo'Burg for a few days.

Is there a cheap car rental in the area? Here in the USA, some places have "Rent a Wreck" car rentals that are much cheaper than the big companies. Any pointers will be appreciated.

Thanks,
Tom