So we drove out to Ontario to look at the blue 2005 Prius with 65k miles on it. I finally figured out how to get the Edmunds pricing to account for mileage and options and such. I put in all the options they listed in their add, and then "optimistically" picked "average" instead of "clean" for the status of the car. That came out to an estimated retail value of $13.2k, vs the $14.4k they were asking for. We got out there and found that "average" was a quite reasonable evaluation of the car. It was dinged up in lot of spots, there were a couple very minor dents, and a lot of smudges and scratches on the upholstery inside. Then, as soon as we turned the car on the "maintenance required" light came on, although the car seemed to drive fine. (Edit: Oh yeah, and when we checked a little later the rear tires were worn down to the "replace" level =P)
After the test drive they promised they could get the maintenance thing taken care of by the end of the day, and then we started haggling. They rounded down from the internet price and started at $14.3k, and i started out at $12k, though i didn't stay there for very long. shelleycat says i did a pretty good job of negotiating, but eventually we ended up at an impasse with me at $13.3k ($100 above the Edmunds estimate) and them at $13.7k ($600 below their starting price.) I'd gone from $13.2 to $13.3 in the last round, but he'd just repeated the $13.7, so we walked out.
So tomorrow i guess i get to rent a car and look at some other prospects. What fun =P