Due to solar eclipse event this summer and for those of you who decide to visit US, make sure you look into prepaid – no service SIM cards when you arrive. Unfortunately there’s no guarantee your european cell phone plan will be as cheap as it’s at your home. I’ve experienced personally issues when I was visiting my wife several times in the past. US phone network providers like to charge a little bit extra, causing issues once you get back home to discover a 400 – 700 USD bill at your doorstep.
I will refer to an article from Trip Advisor that explains what your options are,
Finally don’t forget to check that your phone is “unlocked”, meaning that it’s not bound to a specific SIM card provider and also what network coverage each US provider offers, depending which place you plan to visit during your vacations. For example here’s the LTE coverage for T-mobile: T-Mobile LTE coverage map