If we can receive the same merchandise either for free or in exchange for money, perhaps almost all of us will not hesitate to choose the former option, at least as long as this is legal. Learning seems to be a special kind of "merchandise" in this respect.
The truth is that I have been thinking of teaching an intensive summer course on a certain subject. It never occurred to me to charge the participants, as the purpose of the course is not to make money but to promote this subject here in Jerusalem. I am still of two minds about whether to organize it this summer, but as part of theoretical preparation for it I have started consulting other experienced teachers of the subject about this plan (or even dream) of mine. All of those whom I have asked so far told me unanimously that it would be a pedagogical mistake to allow the participants in the course to learn for free and I should charge them for the course, even at a symbolic amount.
This advice of theirs reminded me another advice I had read in a book by one of the most famous linguists-cum-polyglots in Japan: "If you want to learn a new foreign language, you should pay for your learning, even by hiring someone whose only task is to sit still beside you and just listen to you read aloud or speak that language for yourself." This seems to apply not only to learning languages but also to learning other things.
Unfortunately, many of us, including myself, are built psychologically in such a way that if we can learn something for free, we may not take it and the very process of learning it very seriously and may even feel free to quit it very easily. Paying money for our learning surely helps us commit ourselves to what we (are to) learn and persevere.
But in spite of all this, I am also worried that if I should decide to charge a tuition fee, I might end up having no participant in the course as its subject is already known to be not so appealing to many people, especially among the young. So I am looking for some alternative to money as an incentive to commitment and perseverance.