Phone costs about the same most of the malls at least in manila and im sure elsewhere. Have areas where anything mobile phone or ipod like is sold in mini shops. Some new some 2nd hand.
We had a thread about this awhile ago and there are differences im told in certain well know makes between the ones bought normally in the UK and some phill sold ones (nokia is thought to be better if it says made in finaland rather than made in china) many japanese comapnies it products the same happens check where its made, and have heard it again in the prices some of the phone dealers will pay will vary and spares and repairs for various makes may vary.
Phones due to the heat and humidty do seem to been knackered far more quicker out there so do bear this in mind.