He raised his eyes to meet the Dark Creature's, whose shape had grown much more menacing now that she stood directly above him. "Yes... your price..." he mumbled under his breath, lowering his eyes. Milady, what's your price? He thought to himself.
When Darwin first realized he had left the question open-ended, it dawned on him that there were two things to take away from the situation: Alicia was an evil creature. Despite her assurances, he suspected they would settle on a price, with which she would state her price and he would accept or reject. However, the fact that he had not yet received the copies meant that he might have the option to refuse if the price was too high.