Learning a new game is very exciting, especially if the instructor who is teaching is very thorough and patient. When there is no money involved, a person is more likely to teach and take their time with the instructions.
They can even share some strategies that not a lot of people know about. In turn, a person is more likely to learn about the game and all it's rules when the lessons are free. People wishing to learn how to play mahjong can find a friend who has played it a few times. They can also make use of free plays online to learn.