I'm sorry but if you need to sell snakes to put food on the table you are probably in the wrong business. I'm not trying to be mean, I'm just saying that this hobby can be expensive is all. If you want to make money off of it, you probably will, but why not sell closer to market price and get a little extra to put back into the snakes too?
Taking your example, if you have a lovely pied snake and market price is for example $1000. If you sell that snake for $900, you will sell it fast and make a little more than if you would sell it for $600. Why not make the extra money? I guarantee you will make more and get a better reputation this way and have more future sales. Why? Because you are not devaluing your snakes, or trying to sell them off to just make money.