For many lectures, you need your own textbook - which disappears on the shelf after a semester and is hardly ever opened again. Of course, this consumes an unnecessary amount of resources. For this reason there is Studibuch. Here you can buy second-hand literature and sell your own books when you don't need them anymore.

This is so to say circular economy "at its best" ;)

Have alook: www.studibuch.de

Picture by Lubos Houska on Pixabay