I could use a little advice from those knowledgeable here. This will be my first smartphone, as I work from home and haven't the need until now. We have settled on getting an iPhone 6 with 16GB and squeezing by on ATT's 1G data plan. All of this will be manageable for me. I would, however, like to use this phone in Europe should the need arise. Is there anything in particular, either a specific model number for the phone to work overseas or any other advice about ATT that would make my first experience a decent one? What about sim cards? Does the phone come with a sim card or is that an additional expense? Thanks in advance!