Search the web for prepaid calling card info, or go to a store and look at the cards. Write down the customer service numbers and the company names on each card. Take this info and do some research. Make sure you know the name of the issuer of the card and research this company with the Better Business Bureau or a consumer affairs company. If you have the company name and address, The Better Business Bureau will be able to tell you if they ve received complaints about the company.
Word of mouth is also a great way to research a card.
Talk to your friends. Find out what they re experiences have been. If the carrier company is a company you've never heard of, buy a small denomination card first and see if you like the service. The more fees there are, the faster your money will run out. Other cards begin counting as soon as you hit a certain time.