I paid about $5 in Indonesia for a SIM with $5 of credit. It cost me 40% of what it cost to phone across the street in the US to phone the same number from Indonesia!

Whenever you are traveling almost anywhere it is much cheaper to get a local SIM. What with the rules now in the EU you can go into an Aldi supermarket and buy a SIM for each of the phones in your group and talk to each other all over Europe (including Switzerland) for a few cents a minute.

The best place I have found for information is:
Prepaid GSM SIMs

This is not a site that sells, only for info. And remember, almost all of the world (except the far east) uses GSM phones and you need a 3 or 4 band phone, unless you happen to have a European model.