Well, most cell phone companies offer you the choice of entering a contract and paying a certain amount each month, for a pre-set amount of minutes. The other option is to get a pre-pay plan, where there is no contract and you load your phone with money whenever you want, and there is no bill every month. Usually, on a per-minute basis, the contract option is a much better value. If you have an unlocked GSM phone from china, you can bring it over here and use T-Moble or AT&T, the major GSM networks in the US.