Any good Rent a car/Cab Service in Lahore and Islamabad?

I want to know about some of the good Rent a car/Cab service in lahore or isalamabad, I checked out AVIS...but there website says minimum age limit is 21, is this age limit for self-driven cars only? If i want a chauffeur driven car, do i need to be 21 too? i am 19, with a valid CNIC and Drivers Liscence

Radio cab services are available in both cities. They provide the car and driver.

Metro Cab, Avis. If you need Chauffeur you dont need to be 21