7 Digital is a great site to buy music files legally. I use that mainly. Personally I would not buy 500 songs at once, but basically I buy my favs and slowly add songs I really like over time. Innertune is great in the meantime to listen to what you want to without paying a subscription
Honestly I would take the little banner if it meant there was not comerical breaks. The fact that they do this on top of all the ads they also play at breaks is so over the top. I have been getting into European football and I find it so refreshing that they play 45 mins half straight through. It’s way faster games and there is not the disruption of comericals. In those games they have the banner, but I don’t mind it as much