In the field of communication people were happy to have the letter system so that they could have messages delivered across nations
. But its delivery system was totally unreliable and always late. Then the engineers ans scientists came with telegraph, which was fast and reliable but very complicated. So this brought the need and hence invention of telephones, but in its initial stage it was very expensive mode of communication. So now there was the need of getting them to reasonable price ranges. Here cheap international calls came into existence.
Text and talk is used by those who do not wish to pay any daily fees or subscription fees. There is no administration required in this option. All you need to do is send a message with a particular keyword written to the service provider. Just after this you receive a top-up on your mobile phone. You can use the recharge on the same phone or any other phone with a PIN number.
Next comes the free access numbers. This is suitable for those who want to exclude the need of pre-payments, expiry dates and purchasing phone cards. Here you just have to prefix a particular number to the destination number whenever you make a call. This gives you freedom to make long hours of international calls for cheap.
Calling cards give the customers the flexibility to choose among various options, the best suitable card for everyone. Using these you can have low call rates to make international calls. Here you just need to buy a calling card which give the lowest call rates for making calls between nations. The latest way to make international calls for cheap are the PAYG Sim cards. This is the most transparent and easiest way of calling. While using them you don't need to have long term contracts, or access code to prefix or any hidden charges.
With all these options available the call rates are so low that it seems that you are apparently making free calls.