He will transact with her for a notebook and a pen.

...She has her own writing implements actually but what are the pens here like, anyway?

It looks like they favor brush writing but they do have reed, quill, and dip pens.

...uuuuuuugh.  Time to invent the ballpoint at that - no, that's too many projects again, this is the worst possible situation.

When she's stared at the pens long enough the shopkeeper helpfully recommends his favorite kind of quill.

"...fuck, what really makes proper ballpoint pens viable is the ink and I still don't know how the heck the fast-drying inks are synthesized...  Excuse me, sorry, lost in my own brain for a minute there.  ...and even if I can synthesize the necessary formulae, I wouldn't have the industry!  Sorry, I'm just trying to...there's so many problems I could solve with funding.  Quill pens...are not actually good, by the standards I'm used to working with.  But I'm somewhat...caught in a bootstrap paradox's logical complement - I can't make the tools to make these things with because I don't really have enough resources to get started, no matter how many ideas I have that would work wonderfully if I did have those resources."

"What's so great about your pens, then?"

"Well, for one, an internal ink reservoir that I've seen last for months or years of use.  For two, much smoother writing action - ballpoint pens just...glide across the page, compared to any of these, because the nib is a literal ball."

"That does sound nice, though, uh, how does the ink last that long? Is the pen enormous?"

"Not really, no; you make it about the thickness of a finger, and maybe twice the length, and the trick is to have really thin but sturdy and precise construction on the internal components, unlike," she taps an ink bottle, "this ink bottle here.  Maybe the depth of a fingernail, really, and then the ballpoint means that you don't have dripping like fountain pens.  Which are pens with nibs more like that quill pen, but also the same internal reservoir.  And I mostly use pens only intermittently; I really ought to see if I can make graphite for new pencils..."

"We have pencils too." And indeed they do, right over there. These look almost like normal Earth pencils except they don't have erasers attached, those are sold separately.

"Oh, good.  I've got a fancy mechanical one, but replicating that can go quite far down on the priority list."

"Uh-huh."

She can in fact demonstrate this if he wants!  Her pencil is a bright semitransparent orange, and it goes click.

"That's very thin graphite," he remarks.

"Yeah, it's...what, point seven millimeters?  ...Telling you that doesn't help because you don't know what a meter is.  Hold on, I have a ruler for centimeters..."  She has a ruler!  "Didn't even get troported that way.  It's just how it's made."

"Sounds like a pain in the neck but if it works, I guess."

"It's hard to get there, but once you've built the tools that build the tools," she has this almost dreamy or rapturous expression on her face, an outright smile - "well, it's about as easy as clicking this pencil.  That's the sort of things I want to do with my life, now that I'm somehow here.  Build those tools-that-build-tools for everybody."

"...okay."

"...blah, I went off on a ramble again, didn't I?  Sorry!"

"Whatever," he says, and he sells a guy who just walked in a book of sheet music.

Ouch.

Guy who just walked in walks out again with sheet music.

She seems to just sort of...have wound to a stop, for a moment, propped up gently against a wall, before remembering that there's actually stuff she's been meaning to look up in the library for a while.

"Thanks for humoring me; the conversation was pleasant," is her parting comment to the shopkeep.

She wants to go find out what this polity calls itself, where its government meets, and how the heck it secures its food suppliers from things like demons.

This is the city-state of Kuigao. The assembly meets over there. Farmers have cellars they can hide in and signal flares they can use to call in a demon-hunting team if they're cornered in them by a demon; often they also have other boltholes scattered around the farm, or trained animals that can fight off most common demon types. It seems like this does make food more expensive but it's somewhat balanced by the fact that livestock will eat troported food.