When you go to buy time you do not have to take the stick in - just tell them to put money toward the phone number of the stick. Caution - it costs a peso to send a text so when you text you lose part of what you bought - why does that matter? - when you buy $400 for the 399 plan you can send the one text message. If you send it before your previous time runs out they won't apply it and you will have wasted a text. The next text costs another pesos so now you have 398 so can't get the 399 plan. Am I making sense? So go to OXXO and say put $400 on your number and then wait until your time runs out before you text for more. I am not sure at the moment but think the 399 plan would be "alto30" no quotes. When you open the Banda Ancha window there are several boxes around the sides. The bottom left says messages. Click that. Opens another window - click new message - SEND To "5050" no quotes - then in the body write alto 30 and nothing else - and send. It will know what to do as long as you have enough in your account to cover what you ask for. Could seem confusing at first but once you do it is easy. Do a sort of dry run to open the message window and see where to write 5050 and where to write alto30 - alto30 should be the plan for 3GB for 30 days. There are other plans and can be specials online - you can also pay online. So far we have only figure out how to go to OXXO and pay the $400 and do as above - works for us.
Internet on Telcel seems to be very iffy and erratic no matter where we are. If you have line of sight you should get a signal. But most of Mexico is still 3G so if there are lot of people on the web and using data on their phones it can be crowded and slow - but better than nothing. We try to us WiFi as much as we can be have Telcel for those times we can't get WiFi. If Telcel was faster we might use it all the time but it seems slow in most places - no faster than WiFi so we save our data for when we need it. You may get faster speed. I doubt you can stream video or send/receive large files like pictures without using up a lot of your data allotment. A couple years ago we were having files backed up on the cloud and didn't think that everything we did would use data so pictures were going to the cloud and our money went away very fast.