http://www.sueddeutsche.de/f5c38c/1165340/De-Gruyter-kauft-Wissenschaftsverlage.html
Let’s see how the prices of these books develop. Now Claudia Mainborn’s book about the Copula costs 65€ (250 pages). I think it is at least worth 130€ and De Gruyter should increase the price as soon as possible.