Places in riyadh where I can sell my phone?

I have two phones (iPhone 4s 16gb and Blackberry Curve) in relatively good conditions and I was wondering if there are any places in Riyadh where I can sell them

Hey..
U can go to etisalat center in almursalat..next to the ministry of labors...

Good luck..
Liliyan

Mursilaat in front of sahara Mall