Hello,
I like to share my experience how save my money with international roaming. it was my local USA number and i was in Vietnam. As usual i get less call from my known person.
But it was next day of bday celebration. which is normally happens too much calls in a day which is total to one years calls.
that time i was in Vietnam. So i planned that, i will buy local number and divert my call to my international.
I count, i got 120 calls from known persons. which save me around 200$ of roaming.