Wizards will also eventually not be allowed to learn from scrolls that aren't on their spell list.
The gold cost is simply streamlined in the game, because otherwise you would constantly be on the lookout for someone selling paper and ink. At least that's what I would assume.
Yes, that would be a pretty difficult thing to do at the start, I wouldn't expect a refugee camp hiding in a hollow to have a large quantity of expensive paper and ink. Streamlining it is fine.
