It is called a three way calling. What do you is. Call a friend. Tell them you want to do a three way calling. Then you use the flash button on the phone. If there is no flash button push the button as you would hang up the phone. Don't hold the hang up button to long or you will lose the first caller. Then you will here several beeps fast. Then the Dial tone. Call the number. When you are down hit the flash button or the hook button, IE the hang up button. Then you will hear the phone ring. Ask the first person on the other line if there are there. When the third party answers the phone tell them you and your friend is on the line with you. When you are done you can hit the flash or hook button and talk to the first person. And if you don't want to talk any more say good bye and hang up the phone. This will work for you and all that would like to know this type of item has been around for a long time if you would like to know email me at my user name.no you do not have to pay for it.