What is a good thesis statement for A Christmas Carol?

It might be interesting to argue the idea that Scrooge wasn't always such an unpleasant and greedy person, that the conditions of his childhood paved the way for him to become avaricious later in life. There's a good deal of evidence to suggest that a difficult childhood, where Scrooge was abandoned at a miserable boarding school and alienated by his family, made him prioritize money over everything else. When the Ghost of Christmas Past takes Scrooge back to his past, the old man "wept to see his poor forgotten self as he had used to be." His younger self has only a "feeble fire" and is all alone in this school, where there is "too much getting up by candle-light, and not too much to eat." An empty belly and small fire could certainly contribute to Scrooge's acquisitiveness; he certainly would not want to return to this position later in life. Further, when his sister comes to collect him, she tells him, "Father is so much kinder than he used to be." This is a rather troubling line: was Scrooge sent away by an unkind, even abusive, father? How bad was his very early childhood? How did he come to be totally abandoned in this sad place? We cannot know, but the conditions in which he lived at the boarding school certainly seem to betray either a lack of interest or neglect on his father's part. In thinking of this, we might grow more understanding of Scrooge's desire to acquire money—since money wouldn't abandon him and would, instead, provide him with the security he lacked as a child—especially after Belle breaks it off with him as well.

When writing a thesis statement it's always important to bear in mind that you're putting forward an argument. You need to have something you want to say about the story, then be prepared to argue your case, backing it up with evidence from the text. There are a number of potential arguments you could use in relation to A Christmas Carol. For example, you could argue that Scrooge has only really changed his ways for selfish reasons. In that sense, he remains as selfish at the end of the story as he did at the beginning, albeit with a radically different effect upon other people. The Ghost of Christmas Future gives Scrooge a frightening glimpse of what lies in store if he doesn't mend his ways. He's absolutely terrified at the prospect, genuinely concerned at the fate of his soul. So perhaps it could be argued that Scrooge's dramatic conversion is motivated, not by a genuine desire to improve the lot of his fellow man, but by fear and self-interest. For Scrooge, it's all about doing whatever he can to save himself.