There is no such thing as a "het spider". The fact that this guy that is selling snakes is not aware of this is a huge red flag. Also if he doesn't have proof that he has a "het pied" then don’t bother. Proof being papers, parents, and/or siblings. I personally with never buy a het anything unless I know the breeder well and can see proof that the snake is in fact a het. A lot of times on CL you see ppl sell normals as "hets" in order to sell faster and/or boost up the price on a normal. Typical so-called hets you see on CL are piebalds and albinos. I'd be careful, because not only are you buying a young snake that you'd have to raise to breedable size and weight, but you are spending time, love, money or a project with expectations. If those expectations aren't met because you bought a normal thinking it was a het for piebald and you are ready to breed a couple seasons from now, you're going to be seriously disappointed.

For example I have a spider possible het albino. I know he's a possible het (66%) albino because I seen his parents and know the breeder well. 66% het meaning there is 2/3 chance he is het for albino. Example: take an Easter basket and put 3 eggs in there. Two are filled with candy and one isn't. Pick one and hope you get candy... het being the candy. Now I'm going to breed him to my female albino a few seasons from now just to prove him out. I'm not expected him to be het albino, but I'd love to get lucky. I will be shooting for spider 100% het albinos and I know I will get at least that.

So be cautious when it comes to buying hets off CL with no proof. I'm starting out this year and have been working with honest breeders in my area and building good working relationships. Not only have they guided me in the right way, but have helped me start my collection. So that's really all the advice I can give.

Hope I helped,
Vitto