Without reading the story, it's impossible to know for sure who the main characters are. But based on the title, it seems likely that there is a character who is in some way associated with the star money. This could be a finder of the star money, a keeper of it, or someone who is affected by its presence. There may also be other characters that are introduced to create conflict or to help the story progress, like a character who tries to steal the star money or a character who helps the protagonist understand the true value of the star money.
Since I don't know the specific 'the star money short story', it's difficult to name the exact main characters. However, it's common in short stories that there is a central character, maybe a poor person who is suddenly faced with the star money. There might also be supporting characters such as a local merchant who the main character interacts with regarding the star money, or a friend who gives advice on what to do with it.