I have to call my in Pakistan regularly for which I buy phone cards in order to save money. There are a large number of calling card and phone cards available in the market that offer good quality and talk time. Instead of going out and buying phone cards at the shop, you can buy it very easily from your home. GetMeCallingCards.com is the website where you can find any calling card for virtually any destination. It is one of the largest retailers of phone cards.
If you have families outside United States and you call them regularly to keep in touch with them I would recommend you to buy phone cards through GetMeCallingCards.com. You will get best return for your money.