When the occasional " how much " inquiry comes in I usually reply with an optimistic, upbeat response.
Might state something like, " thats' a great name, thanks for inquiring" and " looking for a serious, reasonable offer in the" - " low " ," mid" ," upper " XXXX range.
Usually add a line or so that the price is based on comp research and industry related sales data and markets. And I add lines like " look forward to working with you", or " let me know how we can work out a deal etc".
And I must add that most of my domains for sale were changed to Buy Now rather than " Make Offer".