If they were Medium-tier or High-tier talismans, Harry and the others probably couldn't afford to use them, but these were only Low-tier talismans. And for Low-tier talismans, Ye Feng could simply make a mold and print them directly.
This meant that as long as Harry and his friends could gather the materials themselves, all they needed to do was ask Ye Feng to help mix the spiritual ink and borrow the talisman-printing mold. Then, they would have as many talismans as they could possibly want.
As for the materials needed to mix the spiritual ink...
Chapter 319