New Job Idea...
 

A paper factory so people with writing pen can make books because it's hard to find blank ones!Hmmm here's how it works you get boards and bomy skins and you make the wood into paper and you use the bomy skins to make the cover for the books.here's some stuff that it should make:

Blank White Scroll-Like 10 Piece of paper
Blank Yellow Scroll-5 Paper
Blank Tome-10 Paper and 2 Bomy skin
Blank Book-10 Paper and 4 Bomy skin

What exactly are books useful for?

Writing Stuff...

And Wood wouldn't be used... It's too hard with the Primitive Styles Graal's World is revolved around. Instead make it where you collect reeds and do it like they did it pre-modern times.

Ink and feather?

No, he means produce papyrus instead of paper. But a quill would make more sense than a pen. And you should get different colored inks to change the color in the books.

Or you can just use the post office to write letters, which are relatively cheap

Use the skin for the parchment and the wood for covers, like they did back in olden times. Really. Look it up.

Or how about just seling envelopes at the post office which could be a container for letters? Then people could make books by buying letters for pages and have the envelope be the cover.