I'm planning a trip to Los Angeles, USA in the near future. I bought an unlocked Motorola Photon 4G on Ebay, and currently use it in Argentina. It is in my understanding that USA domestic GSM towers are blocked. I currently have it running Gingerbread 2.3.5. It is also in my understanding that Sprint offers only plans under a contract (Correct me if i'm wrong). What options do i have to use my phone under a prepaid plan with voice, sms and data during my trip?