Here is some of what you might see on the Telcel website. . .
(download and install Google Translate if you need to see these instructions in English when you go to the Telcel website)
http://www.internet.telcel.com/paquetes.html#tab1
These are the planes. We usually get the alto30 - 30 days - 3gb - $399mx
The trick is how to pay and apply - this is what you must know and understand before you leave the Telcel office - and be sure to go to a Telcel company store and not an authorized reseller.
At the bottom of the plans see . . .
" Text Messages (SMS) sent to the dialing 5050 are free.
Activate the service here or send an SMS to the 5050 dial with the key service you need: "
There is a way to do this online but if your plan has run out you may only have the text feature working - I am not sure as we have not done it. So before you leave the Telcel office make sure you know exactly how to do this using your computer and your stick.
When you need to buy more time you can go to any OXXO store as well as Telcel kiosk authorized retailers. All you do is give them the phone number assigned to your stick and tell them how many pesos to put on. They can only do certain multiples - like $200mx - so you apply twice to get to $400mx - or maybe they have $300mx and $100mx. The main idea is you need to get at least one pesos more than the plan - so buy $400 to get the $399 plan.
Now when your expired plan runs out - either by data use or day limit - you go to the Telcel program that is install in your computer and go to the Text window and put in 5050 in the space for number to dial to send the text to - and in the body of the Text you write in the exact plan you want and NOTHING ELSE - So if you decide alto30 is for you you just type that in exactly and send - you are done.
If you do not do this (experience tells us) the money you applied to your stick phone number will see the stick as a phone and will use up your money as phone use minutes instead of plan use data. Here's what that means - as soon as you connect as a phone the money goes away for all the minutes you are connected. BUT if you connect as a data plan the money goes away as you use the data. WHAT IS THE DIFFERENCE? You can stay connected to the internet all day long with the data plan but if you are not using date - in or out - the money does not go away. But if you use it like a phone it will go away every minute you are connected. So making sure you know how to apply funds using your computer and texting 5050 to tell Telcel what plan to apply the funds really matters.
Hope this is all clear - if not be sure to go over it with the people in the Telcel office before you walk out the door.