My home country phone is Verizon.   To use it outside the United States, Verizon offers either a $5 Daily Fee (good for a 24 hour period and automatically renews until cancelled; watch for the text message instructions)  or  a Monthly roaming option which need to be activated and then cancelled upon return. It is a later model iPhone which does supports GSM network frequencies when aboard.    However, I have concerns about it getting lost or stolen.

An Unlocked (GSM) iPhone 5C can be had on eBay for around $50 to $75.    Unlocked mean you can put in SIM card from any carrier.  If you put in a known good SIM and get "Invalid SIM", then the phone may not be unlocked. Verify with the seller!  Also make sure the phone has Clean ESN (electronic serial number), that is, not lost or stolen  and it must be iCloud unlocked. (again, if seller doesn't know or can't remove iCloud password, it could be stolen)

I travel frequently thru out the Americas and Carribean for business purposes and in some countries, am only there for a few days or come infrequently which doesn't justify purchasing a local Prepaid SIM.    SIM card balances (saldo in Spanish) are only good for some number of days or weeks.    When the balance expire, they either are forfeited or they can be recovered if recharged, which means adding more funds, (recarga in Spanish) within a certain time period.   If a SIM card has expired or zero balance for some number of months, the SIM itself can expire meaning you will have to purchase a new one!  Some SIM cards won't work outside the country so have no way to check or recharge. 

I had first tried "global SIM" services from various providers. I won't name names but suffice to say, they are expensive such as:   $2 to $20/MB data, SIM expire after 6 months, minimum reload $20, not work in every country, etc.

(From here on - all prices with $, unless otherwise specified, is in Mexican Pesos or MXN.   As of January 2018, the rate is US $1 to MXN $18)

Telcel is a Mexican mobile provider, part of Carlos Sim's America Movil, also known as Claro  thru out Latin America and the Carribean. 

Amigo/Amigo Sin Limite  is the prepaid SIM service.  You can purchase the SIM for about $150, which comes with an initial balance,  at any of their Customer Service centers (centre de attencion)    They also have a large service center in Terminal 1 of the Mexico City Airport.

• Calling out to Mexico, USA, or Canada is $0.0142/minute
• Sending SMS messages to Mexico, USA or Canada is $0.85
• No cost to receive SMS messages from Mexico, USA or Canada
• Data is $0.85/MB when in Mexico

Direct Link to this page

Packages can be purchased if you are staying in Mexico for some time such as $50 for 7 days of 100 MB. 

Direct Link to this page

You can easily recharge at Telcel outlets, any kiosk or store with the Telcel sign, and all OXXO mini markets (they are everywhere!)    Just give them the phone number and the amount. 

Card balance validity depends on the recharge amount:

• $10 or $20 - 5 days
• $30 - 7 days
• $50 - 15 days
• $100 or more - 30 days

Direct Link to this page

To check balance and expiration, dial *133# SEND

This is the important part:  when the balance expires, you have up to ONE year to recharge!   (Today is January 14, 2018.  Expiration date is January 11, 2019.  Remember, most of the world use Day/Month/Year format)

So there is minimal cost to maintain the SIM when not traveling.   You can still continue to receive incoming SMS messages free, making it ideal for banking alerts and two-factor authentications. 

Now when you are not in Mexico, the Roaming Rates apply which are very reasonable: (and sometimes there are data package deals)   3 pesos is US 16 cents. 

(In my next post, will explain how to setup a "Mi Telcel" web account so you can check balance and recharge online, which is necessary when not in Mexico)

This is my first Steem-It post. Comments and votes are appreciated. I wanted to share with you a solution to a traveler's biggest issue - keeping in touch and minimizing cost of international mobile phone usage.   It is for safety and security reasons, one should always have means of communication which includes your family knowing your location (Find My Iphone or Life360) and having data for email and using navigation and transportation apps (Maps, Uber, Bus/Metro/Subway, Airline/Hotel, ...)  Future topics include tips and cities visited.  Happy Travels!