Billion Racer

Issei Zenya, a young man living a life of extreme frugality, working part-time both day and night. One day, a mysterious woman asks him to become a millionaire... He refuses the offer once he learns that the way to do so is gambling, but after becoming penniless overnight, his heart enters the world of "auto racing" and he finds himself in the middle of it.

(Source: Young Jump, translated)