What  about  Phone Cards ?   Global Phone System  

Phone Card True Cost Calculator

Put the information from your phone card (read the fine print!) into this calculator and click on the "Calculate" button.  If your card doesn't charge you for something, you can leave it blank.

Cost per minute (in cents):  
Connect Fee (in dollars): $ (0 assumed if blank)
Billing Increment (in seconds)   (60 seconds assumed if blank)
Minimum call length (in minutes)   (Omit if same as Billing Increment)
Length of call (minutes:seconds) :
Real cost per minute: $
Total cost of call $

This calculator is simplified.  There are often other costs associated with phone cards.