A name to attach to the origins of the manuscript

[Mark Knowles]

he must have been quite wealthy to have afforded the vellum and inks needed for the manuscript

On the contrary. As Lisa already noted, the vellum is of poor quality and he used every inch of it, down to its irregular edges. 

I have been trying to get a clearer answer to this question as I had always heard from other researchers that the materials used to produce the manuscript were expensive. This seems to be the impression online from searching. So, how much do you think the vellum would have cost?