I am going to Paris for 9 days this New Years. I'm from Chicago. I have an older iPhone 4. It was on the AT&T network. I have it factory unlocked now. I am hoping to use these somehow as my main device for reference while in Paris. My question is what is my best option? I was thinking about buying a SIM card and have it activated for 1 month. The problem is, I am going on December 26-January 4th. What do you guys think?