Telephones are the best way of remaining in touch with each other. For this mode of communication various phones are in use. Like the landline phones, the cell phones and the IP (internet protocol) phones. For the billing of these phones a deep and a fool proof practice has to be in place. It is expected that the billing system be easy for the client to use, and at the same time it should be fool proof.

Conventional method of billing for telephones is the one that is used typically for the landline phones. These bills are typically the ?post paid?. That is, a bill for the calls made, is formed to the client, after the calls are made. Such bills are for a particular time period, say for a month. With the advancements in the billing systems concept of prepaid calling cards came in to existence. These calling cards are easy to buy and very convenient to use. A very unique aspect of these calling cards is that the user can actually check his/her expenditure for the telephone calls.

A calling card is also some times called as a phone card. It is similar to a credit / ATM card in looks and size. The phone services can be paid for by these calling cards. There are two billing models on which they operate. One is a prepaid credit model. Here the client pays certain amount and get a calling card with that amount as a credit. The second model works like a credit card.

The kind of model that is used to make a call using the calling cards depends upon the telecommunication system. However, presently, the most frequent type is the prepaid type of model. These calling cards are available for a certain amount and the cost of the call is deducted from the balance on the card. When the balance becomes nil a new card has to be bought. These calling cards are disposable.

There is also another type of card available which has a PIN (Permanent Identification Number) that is written on it. By using this number a call can be placed and the charges are billed on a pre determined landline number.

Almost all of the phone service providers offer prepaid calling cards to their users. Therefore there is a stiff competition among the service providers over the rates of the calling cards. It is for the user to choose the cheapest calling card from this wide variety that is available.

One of ways of receiving a calling card is physically buying it from a store. If one looks on the Internet for calling cards there are various options. There are sites were one can have his/her calling cards recharged. Also there are others who offer cheap calling cards right in to ones e-mail box. That is the calling card is emailed on making the payment for it through the credit card.