It’s cheap because it’s industrial waste that has significant cleanup and disposal costs. It was sold to municipalities after there was “research” that it helped tooth health, which it can in much higher concentrations than is in any water supply. But the reason it’s added to water is because the companies that otherwise would have to pay for clean up now make money off the waste product and can afford kickback funds.
Music licensing is a nightmare. Music licensing across international borders is a ridiculous surrealist nightmare from which you can never wake; if you should ever want to enter into such endeavors find the nearest cliff and try to fly as that will be a less painful adventure more likely to find success.