Well, it seems that since we were expecting to hear a number in a certain price range, we didn't listen carefully enough. The price to have the crown molding installed (note that we purchased the crown molding and painted it ourselves) is actually $3.25 per linear foot. Not $325 for the whole house. The difference is going to be about $400-$500. Ouch.
The good news is that I am not terribly upset about this because the only alternative we had explored was doing it ourselves, which likely would have resulted in a lot of wasted supplies from bad cuts and a lot of time and frustration since we've never done it before. I also don't consider myself to be very skilled at things that involve precise measurements, so I didn't really trust myself to do the job well. We probably wouldn't have gotten the crown molding installed for a long time. And it was something I really wanted. I think it makes a huge difference in the niceness factor of a home for a relatively low cost. Kind of like a fresh coat of paint (albiet not quite as cheap).
I'm also not too upset because we've gotten what we feel are great deals on the other work we've had done on the house. All in all, we feel we're still coming out ahead. Plus, we got a great deal on the crown molding itself. If you buy individual strips of crown molding at Home Depot, you'll pay about $1.24 per linear foot, but if you buy the contractor packs, you'll pay about 1/3 of the price. A Home Depot employee was nice enough to tip me off to this fact. The catch is that they only sell a few types of molding in contractor packs, so your selection is very limited.
And honestly, I feel fortunate that the financial mistake we made was relatively small when you consider the big picture. We can still afford to pay the bill and it isn't going to ruin us financially. What this experience has taught is, though, is that making deals over the phone perhaps isn't the best way to go. If we had gone to the store and gotten the deal in writing, we would have seen clearly that the deal was $3.25 per linear foot, not $325 for the entire job. Also, it's important to listen carefully to what the person is actually saying, and not to assume that they are telling you what you're expecting to hear.