One thing for sure DON'T take b$$$  as you will get charged a whopping  fee for roaming plus whatever else they can.  Either take your phone south and go to a local store and buy a sim card or even by a throw away phone for under $40. and use it and then keep it or throw it away after. While I was in Mexico that's what I did bought a cheap  phone  with sim card and cost under $40. which lasted me longer than a month as the condo didn't have phone service