Metal Machines are a discount set of cars released in 2018 under the Zuru name.  The cars are light, but surprisingly quick.  They can still be found at retailers like Wal-Mart and discount stores.  They come in 3 packs and single car blisters.   It's not clear if they are still planning on producing new cars.  I have three of them at the competitive level: Escape (also called Bandit), Signal and Typhoon.  Since they're so inexpensive, I've picked up about 50 of these cars to see if there is variation in speed. ​