CallCalculator.com
Presented by GlobalPhoneSystem.com

Domestic US example

You buy a phone card on Saturday for $10.00

Fine print on card:

Saturday night you call your girlfriend/boyfriend for 60 minutes

Sunday night you call your mother for 15 minutes:

Saturday you call your girlfriend/boyfriend for 60 minutes:

Sunday  afternoon you call your mother and get her answering machine.  Even though you hang up immediately, this is considered a 1-miinute call.

Sunday night you call your mother for 15 minutes:

And so it goes.  By this time you have made 151 minutes of calls at a cost of $5.56.

This is a per minute rate of 3.68 which is a LOT more that the 1 printed in big print on the card!