I live in the us, my cell provider is Att. I am heading to my first Overseas trip to bali in april. I have a galaxy s3 phone and would like to keep in contact with my family while gone. Should I buy a prepaid calling card here in the us or buy a new sims card in bali & will it work in my phone? Also I have been told about skype, is the free wifi in most villages? I will be there for 12 days. Any info would be great!