To make a phone call, you dial the access number, enter your PIN, and at the voice prompt, enter the phone number of the party you're trying to reach. Typically, each unit equals one domestic minute. Resellers buy telephone minutes from carriers. Issuers set the rates and provide toll-free customer service and access numbers. Distributors get the cards to retailers.
Retailers sell the cards.
When you buy a pre-paid phone card from a store, it's important to remember that you've bought a telephone service, not a product. The store doesn't control the quality of the service. To make sure you're getting what you've paid for, you may want to buy a small denomination first to test out the service, and check with friends or relatives to find out their experience with the card. As the pre-paid phone card industry mushrooms, and as more people buy and use the cards, some problems are coming to light. Look for the rate for domestic and international calls on the card's package or on the vending machine.