We will be in PV for a few days and then Nuevo Vallarta for 10 days over xmas with our fam and I would like 2 cell phones (for my husband and me) so we can text each other. No international calls needed - we can skype if we need to. We are coming down form Canada and both have iPhones. Should we bring an old phone down and unlock it with new SIM card? Buy a cheap phone there? Any guidance most appreciated.