You have to find out what kind of network is being used in the South American country, is it GSM or CDMA? Those kind of sound like meaningless words, but they specify the kind of technology the cell phone uses to communicate. So if you choose the wrong one, then the cell won't be able to communicate. Find out what the network is, then find an unlocked phone here that is compatible with that kind of network. What is an unlocked phone? I'm not too sure exactly, but that's what people advertise the phones as, you then just stick in a SIM card and you're good to go.