I think it is perfectly reasonable for spellbooks to be valuable. Heck I think they should be -very valuable- because to the people that need them they are as good as magic items.
But your method of pricing goes against AL rules.
Step 1: does the module say how much it is worth?
Step 2: If no, then see what the PHB/DMG say it is
worth.
Step 3: if none of those sources list a value, the item is worth 0.
But your method of pricing goes against AL rules.
Step 1: does the module say how much it is worth?
Step 2: If no, then see what the PHB/DMG say it is
worth.
Step 3: if none of those sources list a value, the item is worth 0.