The internal conflict is not having that much money. Neither the husband or hester make enough money to support the family.
It says “Although they lived in style, they felt always an anxiety in the house.There was never enough money. The mother had a small income, and the father had a small income, but not nearly enough for the social position which they had to keep up” (Lines 16-19). She then goes on to explain the definition of luck to Paul.She tells him that luck causes one to have money, that which causes one to be happy.
The short story never explains whether Paul is on a winning streak or if he has something supernatural going on that lets him be able to learn the names of future winning horses if he rides his rocking-horse long enough and hard enough. Eventually he kills himself with his intensive actions on the rocking horse, but it is visible at the very end that his mother still does not care or love him. She accepts his death without showing any signs of grief. It is ironic that the paul considers himself "lucky."
"I never told you, mother, that if I can ride my horse, and get there, then I'm absolutely sure - oh absolutely! Mother, did I ever tell you? I am lucky!"(Lines 469-470)
Its concluded that how the mother’s behavior towards her family, primarily her children, her lack of care and gratefulness for her surroundings and fascination over getting more money proves that money has corrupted the family.