Advice for Northern Italy Sterzing-Vipiteno
 

I will be spending three weeks in Sterzing-Vipiteno in July, flying into Munich then riding by bus to Sterzing-Vipiteno. I have an unlocked smartphone and would like to get a SIM card with prepaid service for data (internet) and calls to the the U.S. and any local numbers I may need to reach.

First of all, will I have any problems with Italian phone/data service being so close to the border, or even traveling into Austria? Should I look for a SIM card in Munich? Would the service work in Northern Italy?

Sterzing-Vipiteno doesn't appear to be a very large city, and I don't see any Wind or Votafone sellers there. Is there a way to get a SIM card by mail in advance (this doesn't seem to be a practical option)? Or it is likely that I will be able to find what I need in Sterzing-Vipiteno? All suggestions welcome. Grazie

You cannot buy an Italian sim in Germany, you have to be in Italy, of course.
Vipiteno/Sterzing is not such a small town, there should be at least one official shop for the 4 operators and surely some multi-brand shop. No problems to buy a sim-card there.
Of course it's better to make a manual selection of the network since if you leave it automatic you could use an Austrian network, spending a lot of money in roaming charges...

Tim: VIPITENO, ELEKTRO HALLER SNC, VIA STAZIONE 6
Vodafone: I can't find an agent in Vipiteno.
3: STECKHOLZER JOSEF, PIAZZA FUORI PORTA, 5/B
Wind: Can't locate

Just because I can't locate a store does not mean it doesn't exist.