Invisibility is going to be very popular with monsters who want to go out in the world.
As far as scrolls are concerned: Xeroxing them doesn't work. Carbon paper does, even on gray paper where the runes are barely visible for intellectual property reasons, and tracing a xeroxed copy also works fine; a simple spell takes about five minutes to make a stack of four. The spells are available in French and Spanish. There isn't a huge selection to start. But it's something.
They give Angela an after-school job tracing them according to demand so they have more time to discover additional runes and work out additional spells, and they put up fliers in the Avalon advertising a mail-order service.
Bella gets a car. It's a beat-up station wagon, but it works.
Bella has a small business, a vehicle, and a long-term career plan.
She sets about making arrangements to skip the eleventh grade, and Darren follows suit.
The two of them are adorably attached to each other. There is a lot of kissing. Savannah teases them a lot and Bella messes with her and Darren blushes.
By the time summer vacation starts, they have a stabilized price point, sufficient regular buyers, enough repertoire, and a nest egg of money that permit them to rent a small storefront and hire a teenage griffin to sell scrolls in the Avalon. They are on their way out (Savannah accompanying for kicks, Bella driving) to seal the deal and drop off a batch of inventory. Bright and early.
They make scrolls, and then scrolls kept are on their persons at all times. Invisibility, a shield spell, simple healings, and luck spells. Darren's trying to figure out how to get that last one onto an object that can go on their persons, but hasn't managed it yet. He thinks he's closing in on managing it, though. Soon.
Now without new runes to give Bella, Savannah isn't subjected to nerdy teaching talk. She's subjected to nerdy magic talk, instead. "Do you think," says Darren consideringly, "that it's worth the extra trouble of using fur or hair or something just to avoid having to draw out like ten more runes to keep things from catching on fire for the luck spell? It's so flimsy, but I keep having trouble trying to get something made out of metal or the like to work."
"Getting a supply of hair could be a problem, but it could work, once it's spelled we could coil it up and put it in resin, maybe?"
"Hmmm, maybe. We could also give feathers a shot, see if those count to catch fire or not in a controlled setting. They're sturdier than a lock of hair, I would know."
"They still don't hold up all that well, I'd want to put them in something. And finding a supply would be harder."
"True. And I wouldn't exactly find it fun to rip out feathers."
"Which is exactly what I meant. I mean, if we lose one, we can try it, but it'd be way easier to raid my hairbrush and maybe Savannah's - your hair probably isn't long enough to use easily - and Angela's I guess."
He nods. "I could always grow my hair longer, have it flowing in the wind behind me. Pretend to be Fabio."
"Fabio? I'm not seeing it. You're rocking a very different style."
Darren giggles. "I am, aren't I. I would get annoyed with carting around the fan required to properly rock long hair."
"Design a wind spell. Problem solved."
"Cast it when I enter the room, maybe. Have the wind blowing through my hair upon entry and flip it every now and then."
"Sure." Pause. "Is Savannah asleep back there? She has not made one crack about you with respect to Fabio."
"Mmm?" says Savannah. "Oh uh - sorry, I was thinking."
"A wonder of the world."
Savannah grunts in a vaguely disgruntled manner.
"... What are you thinking about?"
"Private stuff, don't worry about it."
"Are you okay? Is there a topic that I need to avoid in the future? You're usually only quiet when you're angry about something."
'Nerd' does not have the vaguely affectionate ring that it usually has. It just sounds derogatory.
"Carsick?" guesses Bella. "Wishing you hadn't come along?"
"Ugh, I'm fine, but I'm getting kind of annoyed that you two keep poking me. Shoo, go back to talking about magic."
"... Are you sure you're okay?"
"I said I'm fine. Shoo!"
"We haven't been driving long, I can turn around if you wanna go home and sulk or something?"