Assistant Manager Recommendations Inquiry

[Toxcatl]

The fast trainer is very expensive so what is the benefit of using it when the cost is same thing like buying a mid age player or super young player

Well, this is strange, because they are not very expensive, but they are rare.
In terms of cash, they are 10-20% more expensive than ordinary 18 y/o player. In terms of tokens, they may be expensive on the market in the first few days of the season. But if you wait for a couple of days, you can buy one for less than 10T. And market is not the only source of FT.
Btw, all FT you are buying should be 18 y/o or, as you said, "super young" =]

The benefit of fast trainers is that they are, you know, fast trainers. They get more quality for the same price of condition during training. They need fewer rest packs to get stars, positions and SA.