I made a Spotify powered app ( https://mergemusic.app ) and we didn't add any payment methods to comply with their terms. Tried for months / years to get in touch with someone at Spotify who could discuss a commercial licence agreement, so the app could have a business model. Stonewalled. Turns out Spotify instead of working with us, made their own version - Spotify Blend, launched 2 years after our... - Source: Hacker News / over 1 year ago

Or maybe it'd be like using one of those online beat generators, but instead of dragging over from a fully opened menu you have to unlock them. https://splice.com/sounds/beatmaker or http://sampulator.com/. Source: almost 3 years ago