In mark twain's narrative "i sell a dog," why are the narrator and his friend william swinton short on money?

The reason why the narrator and his friend, William Swinston is short in money because of the reason that Swinston has the habit of buying whiskey in which he loves dearly that he almost spends the money they have on it. This gives the effect on their lives in which instead of having money to save and used in their needs, they lack and are short on it.