i want to ask basically the same question about the galaxy s5, can i use an AT&T gophone chip in it? Or is there any other relaible and not-too-expensive way of getting wifi and phone service on demand with this kind of phone, in the U.S.? I am a missionary, and am in the U.S. only for a few weeks at a time a few times a year. I need a smartphone for GPS services and other telephone and wifeless needs while I am there. If these is,do I buy an UNLOCKED phone, or locked to Sprint, AT&T, or some other carrier? Thanks in advance for any help you can give me - I do not have time or money to make a mistake, need to do it right the first time around, and soon.