Genetics Guide

Long shot but I am thinking of getting into Appaloosa's and breeding them so I'd like advice. I have NEVER strayed from my Mustang's, Andalusian's, Paint's, Gypsy's and Clydesdale's. In all the years I've come back to play I have only done those breeds but for the most part when I really started paying attention to stats and genes its only been for my mustang's. 


I'd love to know what the rarest colors are?
Are there any patterns that most people kinda dislike? 
What is the absolute max you would pay for a decent foal/adult 
what is the max you would pay for a good Stud/broodmare