The best way I have found to price my kitties is a combination of keeping up daily with market prices and also just personal taste. I think that a lot of people tend to price kitties according to how they personally feel about them and I think that's great because chances are other people have the same favorites. I have found that it would be very difficult to come up with a general pricing guide because there are just so many factors, and trends change literally in days.
For instance, yes a non-gen trait could sell for more but even among non-gen traits (specifically eyes) there is a huge difference in pricing because it depends on the rarity. More rare=charging more, typically. And what is rare changes very fast. Also, a cat that would be seen as a "cheap cat" to some could be quite valuable to others. Breeders are collectors, too, and a certain combination of traits on a cat can make a big difference in pricing, even if the individual traits alone wouldn't fetch a lot - if that makes sense.
I know it's more leg work to do it the way I have, but I've found it very rewarding.
Jacey, next time you get yourself a Sable with Mocha Mysterious eyes, you put me on speed dial, m'kay?