Each successful generation deducts 0.03 AI credits from your Sprwt AI balance (the dialog states "This function costs .03 AI credits"). The charge is only taken when at least one meal was actually added, and it is logged in your AI usage history as "Random Menu Generation - N meals". If your balance is below 0.03 the button opens a no-credits dialog instead of the generator. You can check your current balance in the left menu under AI Balance (/admin/aibalance), or in the small "AI Balance: $X.XX" readout in the admin header bar.