It is quite more expensive than spain, that is for sure.
But Germany is, on the other hand, way more populated, so the chance to set up a pilgrim's house is very expensive and more expensive to maintain. If you see all the regulations and rules in Germany that you have to follow to set up a small business or a hostel and that are mandantory and checked regularly by officials, than you are aware that this is a p*in in the a*s.
Germany is not a small-business-friendly environment!
btw: for larger groups (students, pupils, large families) the price per night will drop down up to 12€ (incl. breakfast and lunch) per person in the Jugendherberge. But you have to have a "Jugendherbergswerk-card", that stated that you are qualified to get those discounts.
Another possibility to get an accomodation is the "Naturfreunde". A night from 11.5€.
Check their website:
Maybe this is helpful in any way.
Buen Camino / Guten Weg!