Traveling to canada this weekend with my unlocked iPhone5, normally on Tmob. A few questions: 1. Is it good enough to set the Data Roaming switch in settings to OFF to prevent surprise international data charges, or would it be better to switch the Cellular Data switch in settings to off so that the phone is grunted to use data only when on Wifi (according to the description of the Cellular Data switch)? Is that overkill? 2. Any tips for ways to call/txt back to phone numbers in the US cheaply? I was looking at using my Google Voice number, which is linked to my Taptalk app, to make calls/send texts when on WiFi at the hotel. Any thoughts on that? Any other ideas for when I'm not on Wifi? I see with Tmob roaming, I can recieve texts for free, but its $0.20 a text outgoing, or $0.53/min to make or receive calls. Looking for something i can use to make maybe a 5-10 min call each day to check on in my elderly father, and maybe a few texts a day to other people. Thanks.