The only safe bet is that rarer balls will be more expensive than common morphs, and more striking morphs and combos will be pricier than less attractive ones. Also, when a new combo is produced that is umusually attractive, it will raise the price of its constituent morphs as well as its own value. Remember what happened to FIRE prices after the "FIREfly" (Pastel FIRE) was unveiled? Also the "Spied" after Roussis reptiles posted the first pics....