One of the car dealers is "Mad Man Mutts", a wild man in a cage. This is a parody of Earl Muntz, otherwise known as "Madman Muntz". He became known for his frenetically-paced TV commercials for appliances and, especially, used cars.
The concept of a lemon car, nodded to here, means a model with a significant defect or malfunction that makes it unsafe to drive. The term as applied to cars dates back to the 1920's, although it had been used to denote a bad item purchase at the turn of the 20th century.
The final shot of a car shows a license that reads WL 1899. This would likely refer to animator Walter Lantz, who was born in 1899.