I really enjoy her music and only discovered her after being in Germany for three months. I can only find her music on youtube. For some reason itunes, spotify, and other popular sites barely have any of her music. Does anyone know where I can buy her songs online?
It seems that there's often a link below her videos on Youtube: have you tried them? Interesting lady, anyway…
Top tip: artists have a vested interest in you obtaining the works, so it's usually worth giving their web sites a try. How do you find those? Google.
http://www.jennifer-rostock.de/#section9 states Amazon/iTunes/Spotify ... so perhaps give the German versions of these sites a try?
Also, if you click on 'shop', there is this bit: https://jennifer-rostock.liveyourmusic.com/jrode/
That was just from a quick look - have a good look around yourself.
As far as I can see from a quick glance at Amazon, they have dozens of Jennifer Rostock albums and singles available as MP3 download, streaming, CD, and vinyl. Google Play also seems to have a decent amount of material by them.