Question Looking for a good android smartphone

Phones (at least in the US) are either CDMA or GSM (network type), not both and not interchangeable/changeable. So the only way to know if a particular carrier/service provider can be used with a device is to check if that carrier, or others who are on the same network type have the phone. Plus it may not be brand limited. I mean many companies sell certain models that are with CDMA carriers/service providers and then sell other models that are with GSM carriers/service providers. Any place that is selling the phone should be able to tell you which network it works on. If they say both or it doesn't matter or it will work, try asking someone else. :)