At the end of Ms. Vall. 2297, there is an interesting note by the owner, a 15th century chap named Sozomenus, about whom I know nothing except that he owned manuscripts:
Melius est emere libros iam scriptos quam scribi facere: nam pro membranis exposui grossos tredecim, scriptori dedi libros duodecim, et cartorario grossos quatuor. Summa ergo in totum libras sexdecim solidos tredecim denarios vi. Die primo mensis Martii MCCCCXXV.
It is better to buy books already written than to have them written: now for parchments I am out 13 grossos, I gave 12 to the scribe of the boooks, and 4 grossos to the binder. In total therefor in all books 16 solidi, 13 denarii and vi. 1st March, 1425.
The “grosso”, or “denaro grosso” — “heavy penny” — was an Italian silver coin, heavier than a silver penny. The name is related to the medieval “groat”, I believe. It cost the owner 29 of these to have these books copied.