The prime example of this is Manchester City's Gabriel Jesus.
Anybody who has seen the Brazilian forward play will be aware that he's clinical in front of goal and always makes the most of his playing time. The problem is, at £9.5 million, can you really afford to spend nearly 1/10th of your transfer budget on somebody who is largely going to be a squad player used as an alternative when Sergio Aguero needs a rest or has an injury?
To put this into perspective, 22 other striker options scored more Fantasy points than Jesus - and the majority of those players were in the £6 million - £7.5 million bracket.
It's all well and good being tempted by one of the glamour names at one of the Premier League's bigger teams, but for you Fantasy Football team you need to be investing your budget wisely. And that means you can't afford to be paying out heavy fees for players who aren't going to be starting at least 80% of the team's games.