My U.S. A. phone carrier (Assurance wireless) does not provide out-of-country service. I will need to purchase a new plan while I am traveling in Mexico. Should I buy a limited minutes phone? Use the phone I have and change SIM card? Buy here or wait until I arrive in Mexico? I do not need data or anything fancy. Just a way to communicate with people back in the U.S.A. either by talk or by text. I will only be traveling for just over a week.