ahh pet stores will do anything to make money! but i think it's crazy they would charge more for dumbo, or blue.
Mine is pretty bad, but same colored rats are sold for the same price.
We have blue rex, blue dumbo, blue normal coated, siamese dumbo, siamese normal and those are all sold as fancy rats and are the same price.
We have one hairless rat that is one dollar more, because i was told that snakes don't digest fur very well and some snake owners want hairless rats to feed their snakes, but that doesn't make very much profit because they don't end up buying cage, cage accessories, another rat to keep it warm, food or anything.
And then the store breeds the same female with the same male all the time (She's already had 3 litters, and they're continuing, and the litters are always back to back and sometimes more often since they freeze the pinkies) and so it's a black/dark brown female with a siamese male that always gives berkshire or hooded black and white rats.
Those are half the price of the "fancy" blue and dumbos, because they are intended for snake food. But some people get those as pets thankfully (LIKE ME!)
my last day is monday, thank god, i can't take the guilt anymore of not being able to do anything for those rats, or all the other animals in there.