You might want to look at AT&T’s Passport plan. It’s what I mainly use when I’m outside of the U.S. now. It’s quite easy to use and it makes life much easier for me now. Below is part of a post that I made earlier on FT:
“.... my carrier is AT&T and I'm ONLY using their Passport plan, to make/receive calls, send/receive texts and use cellular data while I'm overseas. It's $10/24 hour period (not day) for unlimited texts, unlimited phone calls and cellular data up to the limits of your plan. It works just as if I was back in the U.S. At the risk of repeating myself, it works like a charm.
If anyone wants more info, you may want to check AT&T's Passport plan page or similar page for other carriers. It really is quite simple and not as complicated as others are making it.”