A former facilities manager where I work used to get quotes just so he could say no to the person who wanted the project. You can't say no to a project without a price. Even if he never planned to do the project, he had to call up a contractor or 3 to get a figure so then he could say it's too high.
As a former telecom sales weasel, I emphatize with the guy on the right in attempting to gain clarification (should he go back and marshall the troops to work over the weekend creating a proposal that doesn't have a snowball's chance in hades?).
In any case Sales 101 forbids the wearing of a green tie (it reminds the prospect of $$$).
If the sales guy really wanted to be evil, he could give Dilbert the quote but make it so low that Dilbert would have trouble explaining why they did not go with that vendor. Then if Dilbert's company decides to go with them, they can simply tack on a bunch of fees and "extras" that were not included in the original quote (i.e. the car is only $20, but the tires, seats, engine, etc. are extra).
Dilbert's problem is that he turned him down in a private meeting room. He should have made the sales guy take him to lunch and then break the news there. He should take a note from some of his dates.