I find Deira City Center is the mall that is easy to get to and noticeably cheaper than most other malls for both electronics and other stuff. It is only a few stops from airport. It has many shops selling phones such as Sharaf, Axiom and Carrefour. You should push for a discount off any list price and you should check prices in a number of shops first so you can bargain. Carrefour is good and you can bargain in there.