Boni and Clyde tandem was a success that they become popular. However, all thing have an ending and theirs is their crime. Boni remembered this well, so she contacts Clyde to go back to their crime wave. They need to buy a car before they can go back with their crime.
Buy a car with the money at hand. Drive the car as fast as you can till you reach the safe place. Aside from the dangerous road ahead, the cops will be on your trail most of the time. You need to destroy it as fast as possible and get on your way.