What sort do you mean for the car? Like a In-dash by removing your current CD/FM Player or Stick-on?
Anyways i'll answer both,

In-Dash (removing current music system)
I myself have a in-dash system, I took out the Bose system and installed the tv screen from Kenwood, Costed 1700QR, brought from Lulu Hypermarket, 100QR for installation.
I have a years warranty comes with AUX/USB/IPod Connect/GPS/MP3 CD/Audio CD and many more functions. Got as much as i paid. 7 Inch Touch Screen with a Volume Knob button (Dont like the click volumes)

Stick-on
Any Carrefour supplies that in the Mobile Telephones Section. They range from 300QR to 1200QR depending on your functions. Its a simple stick-on that attaches to your wind screen through a suction pad and charge it through the cigarette lighter.

Hope it helps.