Let's pretend that at the $0.99 you were actually losing money, no profit, not even breaking even.Any tips on a civil way to tell your customers that will create an impact on them to realize that their demands are impossible?
What would your response be? You would be absolutely 100% sure that you would not take this job at that price. But the fact that in your mind you are probably calculating and recalculating profits as the discussion continues softens your argument against it and you may be talked into accepting a bad order.
Just pretend that at whatever prices the customer is asking that you will be losing money taking the order. You will find yourself in a different negotiating mindset.
I would just tell them, "I'm sorry but we cannot do your order at that price. Our best price is XXXXX and if this is acceptable to you we can get started on it right away."