Your really gonna have to shop around for that. That outback you listed before I thought was'nt that bad of a price. The age of a yak IMHO should'nt be too much of an issue as long as its been well kept, and minor scratches. 2004 though is gonna be a little out of date with finding some spare parts for that mirage drive. They changed the setup in 2012 I believe to make it easier to get in and out of the boat. Also the drive mechanism was upgraded. Bottom line, Hobies are an expensive boat. There are a TON of mods you can do a yak though. My friend has a little electric trolling motor he uses. Then theres some I saw on youtube with 5 hp 4 stroke. But keep searching around. If you don't mind road trips, expand your search. You may even wish to get some roof racks now, if your very serious about finding one a bit out of the way. This way you can just pop out, and grab it if its all its claimed to be. Good luck with your quest though, and again the show is coming up. Its a new year dealers want to get some old stock out.
Cheers M8