How can you tell if someone is a fast trainer or not?

[TimYoung]

Age and there price the younger the age + higher the price tends to mean the fastest of trainers.
But you can get 18 year olds that are slow trainers these are much cheaper.
For e.g. on your level 3 now? it'll be about 3mill to buy a 18 year old fast trainer and about 1.5mill to a buy an 18 year old slow trainer^^

Okay ta. So it is base on price. What happens if someone just jacked up the price when selling their players to the max? Is the price difference so big that you can still tell?

Yes I am in Season 3 now.