Some thoughts on picking out a garter snake:
I know almost exactly what kind of garter I'd like. I saved a picture of my dreamie garter, seems to be a blue axanthic plains garter. Feel free to correct me, seems the plains garter is Thamnophis radix.

If I bought one of these, I'd get exactly what I'd want. On the other hand, what if I buy one and the garter dies on me over some newbie mistake, I'm thinking maybe I should buy a cheaper / plainer looking one as a first garter.

On the other hand, I'm not really looking to collect garter snakes either so maybe buying exactly what I want upfront might be the best choice.
By choosing the cheaper /plainer cresties, I now have a homely male crestie with floppy tail that I've gotten attached to, but I kinda wish I had purchased a fancier one at that point in hindsight. Keeping him has become a moral dilemma since each male crestie needs their own tank. The moral dilemma being does one re-home animals simply because you now want a prettier one.