I'll be traveling to Budapest, Vienna and Prague from 7/15 through 7/25. I have an unlocked Galaxy S7.

I've read that there are new roaming rules for the EU that went into affect recently. Am I now able to get a single SIM card in Budapest that I can use to get 4G service in all 3 countries that we are visiting?

For example, Vodafone
http://www.vodafone.hu/eng/phones-pl...s-you-go-plans

Can I just go into a Vodafone store and get a SIM only Max M plan and pay 2946 HUF one time and that's it? That would then give me 4.1GB of 4G data for my trip? I would get 4G speeds in all 3 countries?

How would the 100 minutes of voice calling work? I assume I must get a Hungary number, so what happens if I call a local number in Vienna?

I have T-Mobile in the US (I'm not on a plan that gets me free international roaming) and T-Mobile now has T-Mobile Digits. What's great about this is that I can have a foreign SIM in my phone and run the T-Mobile Digits app and still receive phone calls and texts to my US phone number. That would work perfectly for me.