I've seen this formalized as a strategy (probably here on Hacker News): 1. Express disbelief at the offer. You might just repeat the offer with appropriate inf

I've seen this formalized as a strategy (probably here on Hacker News): 1. Express disbelief at the offer. You might just repeat the offer with appropriate inflection and body language, like it's hard to believe they are asking that much. 2. Don't say anything, no matter how uncomfortable it gets. Wait until the other party makes a concession. I suspect professional sales people will be wise to this, but they probably already have a concession they are willing to make to close the deal.