"What is the average of your x previous invoices for x?" = good
Sure I might charge by default $1k for a logo but the chances of $1k being billed every time are slim, every client is different. The average invoice price is the most valuable metric. Every designer will say they charge $5k when they charge $1k because it makes them feel good.
There are several comments here along these lines. I don't disagree that the latter is a better framing of the question, but...
No one wants to hear that they're ignorant. No one wants to listen to a condescending speech about how they don't understand your area of expertise. Take a moment, be patient, educate them a little, try a couple concrete examples, and keep calm. If you can't arrive at an understanding after a few tries you can always walk away. I will assure you, however, that you will secure a lot more clients and referrals if you treat everyone with respect and try to help them find the right solution for themselves.
"What is the average of your x previous invoices for x?" = good
Sure I might charge by default $1k for a logo but the chances of $1k being billed every time are slim, every client is different. The average invoice price is the most valuable metric. Every designer will say they charge $5k when they charge $1k because it makes them feel good.