I work for a web agency.
Over the last 18 months a company asked us about 5 different quotes for rather minimal changes to their website.
While being minimal changes, estimating costs for them still requires several hours of work for research, meetings, correspondance and writing the damn things. They never even gave us a response (neither positive nor negative), except once where they told us that they wouldn't pay for project management because their instructions are so clear that PM isn't necessary.

As a response to the last one, after several months, they send us a 10 pages long pdf with requirements for a new website (or a "restyle" like they call it, even if it has absolutely nothing in common with the current one).
We inform them that we can't permit ourselves to continue studying new solutions for free and therefore tell them that a detailed offer would cost them something like 300$, and that amount would then be discounted from the eventually accepted job. We also roughly estimate a price range of about 15k - 20k for the new website.

We get an email back, from the CEO (until now it was a secretary), with essentially 3 arguments written in condescending form:
1. he brags about his revenue being over 9 billion $$$ a year, and that being a part of a global holding for which "communication is essential" (sic.) means that they need to coordinate and "can't simply accept an offer" [even if it's 400$, for specific change exactly requested by them, I guess...]

2. 15k is too much [... for the website representing this 9 billion dollar holding on the internet, for which the requirements are written in the 10 pages long pdf]

3. He asks for a meeting

We accept the meeting, we go to their office.

When we arrive there, the secretary informs us that the CEO will not participate. So we talk the her and the head of the "Communication Dept" in videoconference.
I explain them that if the sum, which we thought would be appropriate (~15 - 20k), is too high, the Pareto principle would allow us to, theoretically, achieve about 80% of the features and quality for about 20% of the cost. Their genuine response is:
"So your estimate was wrong! You can do it for much less!".
I try to explain them that the most money in a project goes into "attention to detail".
The "Communication Dept." person, who is "doing this job since too much time" (sic.), refuses to believe and insists that "details" don't exist on the web.
I tell her: "In any kind of work, the more effort you put into something, the better it tends to get, with diminishing returns".
She insists: "I don't understand this".

So now I'm here, doing the 6th offer, free of charge, for a 5k website, for a company that generates 9kkk revenue each year, trying to define a "Definition of Done" that works out.

FML I guess.

Sorry for the long post.