Hi, I currently own a iPhone 3G and it has issues, it is out of warranty and I would like to get it replaced. I want to know how much it would cost, since Apple does not sell the 3G anymore which phone would I end up with? The 3GS, 4 or 4S? The issues are the power button does not work, the vibrate and volume rocker are missing and the sim card slot does not work. Thanks