The County Fair (1920)

"The County Fair" begins with a nasty rich guy threatening to turn an old lady onto the street--unless her niece (who lives with her) marries this man's son. While she's dead set against it, the niece is a sweet thing and would do anything to help her aunt--even marry the rich jerk. However, a possible way out is presented. When a poor young man is taken in and fed, he turns out (naturally) to be a jockey and thinks he can win the $3000 prize at the fair and save the farm.