I would be willing to pay extra for box charges for quality animals.
Consider though, that you are arguing your amount of profit rather than an actual cost of the animal. I mean, a corn snake is cheaper to buy but requires the same care/work to get it to marketable size as some other expensive snakes. If you were shipping a corn snake and the cost of shipping/gas, etc. made it so that you lost money or broke even, that might be different. But at $500, the snake better be eating golden mice if you tell me you're losing money
BTW, I don't know a corn from a python so replace these with the proper species to understand my point.