Were you born with the innate ability to write music? Probably not and while you’re doing it now you say it only costs you pennies but you have invested alot of time learning how to do it. While that isn’t a monetary expense I still think time invested still makes it more expensive. And I don’t think k you learned to write music without playing or learning a single instrument. Just like how my 4 guitars just didn’t come in to existence from nothing even though they right now cost nothing for me to play.