A fun thing happened to me when I became a professional musician: I started hearing really high-level music for free all the time. This is the secret that professional musicians don’t want to tell you. Sure, we want you to pay us, but we don’t really pay to see stuff anymore. I spend all day in rehearsals, listening to great artists make great music, and if, in the evenings, my ears aren’t bleeding yet, I can usually get comp tickets to whatever my friends are performing in.
In short, music costs money for you because there are people who are better than you at it. This is basically the same reason why your car (probably) wasn’t free: you wanted a car that actually functioned at a high level, and the one you could have built with your bare hands out of materials you’d gathered yourself just wasn’t good enough. So you bought the higher-level work of a professional. Nobody charges you for whistling melodies you’ve made up to yourself–but if you want something that’s been vetted as the highest-level work, by millions of people, you need to pay for it or learn how to do it yourself.