Goon, for me it's pretty simple when it comes to signing young players. Either
1) It's a highly rated youngster with it all to prove who we take an early chance on, potentially spending decent amount of money whilst tripling his salary in the process (whilst still being somewhere around the 100k mark pushing 150k if we really believe in him),
2) It's a highly rated young player who's proven himself and is worth stumping up 250-300k+ for in addition to a very, very large fee.
We can't compete with number 2 TBH because even if we could afford it those players won't come here generally at the moment. For number 1, we should not be paying the wage that the player in number 2 will be demanding.
What are we going to do when it comes time to renegotiate? Give him 500k? Or if he tanks and we are stuck with another overpaid player not pulling his weight, only difference is unlike Auba and Ozil, this is someone who doesn't have a proven track record of performance over the years. It's a huge gamble.