Cost to produce the Voynich manuscript

[Sephardi_Genius]

Obviously we know that Rudolf II bought it for 600 ducats, 

That is a claim.  We do not know if that claim was true.  I suspect that the Voynich Manuscript was never owned by Emperor Rudolf II but that the claim was invented to make the manuscript seem more important/valuable.

Just out of curiosity, what are you basing your suspicions on? Obviously, hearsay can travel fast, but the fact that the Marci letter was written at least within living memory of the claimed events and there does some to be some indirect corroboration in Rudolf's records that he paid Widemann in the rough amount claimed does seem to indicate some authenticity to the claim. I can understand casting doubt on the idea that the 600 florins were the price paid just for the VMS, because Rudolf's records indicate books (plural), but I feel comfortable chalking up the discrepancy between the price paid for all the books vs. just the VMS and ducats vs. florins as attributable to the temporal distance between the events and the letters and playing telephone between speakers. The signature of Horcicky that appears under UV analysis makes it somewhat undeniable that it would've at least been around the court of Prague. It still seems reasonable to me to disbelieve the claim (its believable it could just be marketing) but I'm wondering if you have any specific material or analytic evidence you're relying on that I haven't touched on?