You don't mention any genres you might be interested in, but you might check out the science fiction novels of Andre Norton. The author was a woman -- her real name was Alice Mary Norton -- and her books should be very inexpensive (or free). She was very well known for writing Young Adult science fiction (but I still like them, even today).
You might try looking for her on Amazon. I assume you can also buy from Baen in Germany (I'm in the US, and don't know for sure):
http://www.baen.com/catalog/category...orton/id/1860/
Have fun!