"Pen friends" are a way of communicating with someone abroad, to learn about how they live and what they experience. Having a pen pal can help in several ways: by helping us practice writing in a different language, by seeing what the other person goes through, and understanding different cultural circumstances.
In this day and age it's much easier to get in contact with someone abroad without snail mail and without needing to pay money. The Internet has brought this at our fingertips through email, messaging boards, instant messaging and other services. Anyone can meet new people if they search in the right places. Additionally, the two people would make sure they had things in common and would keep in touch based on their shared interests. There is also the possibility to write to people we already know, from camps or people who moved away.
So, considering the opportunities of real time communication and choice of people to speak with, it is possible to get a pen friend without paying a fee.
