Final answer:
The passages provided discuss the concept of Santa Claus but do not reveal the specific gift Sally requests, making it impossible to answer the question about what Sally's one gift is.
Step-by-step explanation:
The question asks about the gift Sally wants from Santa. The passages provided do not specify what Sally specifically asks for from Santa; the content given dives into the concept of Santa Claus and the tradition surrounding him but without providing details on Sally's actual request.
The mention of Sally dictating a letter is not accompanied by the content of the letter itself. Therefore, without additional context or text, it is not possible to answer what Sally ultimately asks for from Santa.