[j_s]

Here is the link to the $0.99 ad-free version (rather than in-app purchase) for the lazy:

https://play.google.com/store/apps/details?id=com.dp.ezfolde...

I personally use Vanilla Music (not specifically minimalist but open source and [ad] free):

https://play.google.com/store/apps/details?id=ch.blinkenligh...