I'll be traveling in Europe and plan to take my HTC One so that I can use the WiFi capabilities for email/text/calling using Talkatone or other free WiFi based apps. I know that I can put the phone on Airplane mode with WiFi on get this functionality, but I'm wondering whether this is the best method of avoiding roaming charges or if there are other options. I'm also curious to know whether i can change the SIM card when I arrive in Europe and pay lower calling rates if I wish to use the cell network. I'm also open to other reasonable options to avoid additional charges from my carrier (Verizon). Thanks in advance for any idea, recommendations and advice -