@Thanael
Pegasus has a flat price policy: Every new book costs 20€. There are collections for the smaller, online only publications (Schattenhandbuch 1 und 2).
I'd imagine having a long term deal with a printer and a reliable German fan base (SR has always been one of the more popular systems around here) help them out quite a bit. (Not to mention that they also sell German Translations of Cthulhu, Lord of the Rings, Midgard as well as Munchkin and all Wizard of the Coast things (Magic, D&D)
Quite a lot of action for a relatively small Publisher (Last I read they had 20 full time employees and around 100 free lancers).
All in all just a typical German "mittelständischer Betrieb", with the founders and owners being fans of what they are doing.