I need to bump this topic for a clarification.

Some say : "no the amount isn't a point to spot a fast trainer".
Some say : "yes the amount is a point to spot a fast trainer".

So, I bought 2 youngsters last season, the cheapest of all, and they were all slow trainers compared to when I invested double amount for the same aged player who were decent trainers. What to conclude then ? I was lucky ? It was a coincidence ?

What we must be sure of before buying a fast trainer youngster from the transfer list then ?