If you are using a local sim in Europe, consider forwarding all your calls at home/workto a Google Voice number, and forwarding the GV number to your European number. This provides free service in the U.S. and calls to most European countries at 10 cents per minute. So the folks that call you at home don't get any overseas charges and you absorb a relatively modest fee...cheaper than paying ATT or Verizon on a per call basis to receive service and keeping your number and no surprises for the friends and family back home.
Plan B, which I did on my last trip, was to use a tablet with an earpiece instead of a phone. Cell companies generally don't let you use VOIP on phones, but let you use it on laptops and tablet data plans. The GrooveIP app for Android and Talktone for IPad are VOIP programs that let you use Google Voice over the Internet for free calls to and from the U.S. and, as indicated above, 10 cents a minute for calls to Europe. So, if I called Mom in NY or she called me, it was free. If I called a restaurant down the street from the hotel in Milan for a reservation, it was 10 cents a minute. Mom talks longer, so it worked out pretty well.