Phone Cards
Phone cards are debit or charge cards that are used for making telephone calls. Phone cards come in two varieties: prepaid and tied to an existing telephone account. The prepayment type is where the buyer purchases a card that specifies a specific amount of money or a specific amount of phone time. The card that is tied to an existing account number usually have a PIN that a user has to punch in when making a phone call.
US phone cards are especially popular for calling to India. But they are also useful as Brazil phone cards or Bulgaria call cards.