I just came back from my vacation. One of the best free call
apps that I could find during my vacation was YouRoam. This app only needs internet connection and it enables you
to call anyone, just like a real call. The app also enables tons of other
useful features and it acts as a messaging app as well. But unlike the other
countless spammy and non-working messaging and call apps, this one is tested
and working flawlessly.
YouRoam will also enable you to send and receive instant
messages to YouRoam users for free. It will enable you to send photos and
in-built emoticons. Interestingly, the app will enable you to receive missed
calls, even if your phone is off, and store or check voicemails through the
app. For really small fees you get unlimited calls to any US number.
Additionally, there is a smart caller ID that will help you to see who the
unknown caller is. The app is free and available for Android smartphones and
tablets.