Single allele Dominate and Co-dom morphs are pretty much the same. The only deference between the two is that if you get 2 copies of the co-dom allele it will be visually expressed by a super form (ex: Super Pastel, Super Cinnamon) where as if you get two copies of a dominate morph it would look the same as if it only had one.
So for the market price it comes down to how common the morph is and how much demand there is for it.
Looking around the market it looks like Cinnamons are going for about $25-50 less than Pins, so again, the prices you listed seem pretty typical.