I have bought new cars at knock down prices, they are called pre regs. They are effectively delivery mileage "second hand" cars.
It happens because of the way discounts are given to dealers if they sell a minimum number of cars in a month. The discount applies to all the cars they sell so if they are a few short at the end they will discount stuff below cost to get the discount on all of them.
Once you understand this you can choose what car you want and look for a dealer that is just short of his target and get a huge discount on new.
I have managed 30% in the past, so actually cheaper than the second hand low mileage cars.