That ad is humorous! "Needs new home by order of owner's hysterical mother!" But... I don't know that I'd get that guy, unless they are willing to come down on the "rehoming fee". I haven't paid much attention to prices on milk snakes, but I have a hard time imagining you can't get a baby at a show for that price or less, and then you'll know more about its history, etc.
Of course, if you want the critter cage, etc. that comes with him, that makes it a better deal, but I think I remember you talking about having your snakes in tubs?