I tried having a discussion. They wanted to take it to the vet, but she wasn't sick. And they weren't going to lower the price even after I told them that this snake was going to be dead in a week or two at most. They were simply going to replace her with another snake so the options were dead snake + new snake, or live snake + new snake. And after having 4 of my favorite animals at the shelter have to be euthanised for medical issues that week, I couldn't handle a death that I could prevent. The ASPCA and/or animal control would also have done just about nothing, because she's a snake and because the store would have simply taken her to the vet. Taking the time to do without bringing her home would have resulted in a dead snake.
This is why I said I did not rescue her. Because she's not a rescue. But she is alive, and the store did make some minor positive changes to the habitat after I called corporate. They also loved the idea of weighing the snakes before they ate so they that way if a snake is losing weight they can take it to the vet or keep it in the back to reduce its stress levels for a while.