Advantages vs disadvantages- charging for your app/product

I'm creating an app that lets users mix and create their own songs on the browser. I'm debating whether for the MVP to allow users to download their original songs for free or to charge $0.99 for a download (they can still listen to it for free on the browser).

I know this type of question has been asked millions of times, but I see the advantage of both- if I charge, I can see who really sees the value in the product, but if its free, I can get more users and more input, and look for a revenue stream later.