The dark blue Waffenrock is not really a sought after item amongst collectors. A wise collector once gave me the advice of never buying one unless it was in absolute mint condition.
To be honest, I have never really wanted one, but do have two in my collection, both belonged to August Weber and were worn 1912/13 during his time as a one year volunteer (Einjährig-Freiwillig) in the I.R. 88.
As part of the large group and together with his 1907/10 tunic I am happy to keep them stored away.
Weber had one privately purchased Waffenrock and one for everyday service that had been been issued to earlier soldiers by the regiment.