What about the whole "I'm rich (gold), you know!" line? Where does she get her money?
Nasu	Arc's rich. Not with cash, but gold.
Don't tell me she materialized it with Marble Phantasm?!
Nasu	No, it's real gold. There's a special gold exchange shop for "fugitives" in the Mage's Association. The owner of that shop seems to be a fan of Arc's, so she always has money (gold).

Staff Roundtable - The First Night