Not all races are the same. To even them out, all are created with a certain minimum scale required to participate, in addition to a registration cost.
These scales are the scores that define the range of your koins. As koins win and lose races, their scales points will change.
Newborn koins are known as koinies, and although they are ready to compete from the first second of their lives, they can only do so in races that belong to the Koinie category. Luckily, enrolling them is free!