1. Alisson Becker - Signed from Roma in 2018 - €62.5 million
The summer after Mohamed Salah exploded onto the scene with Liverpool, the Reds made yet another transformative signing. They were coming off of a brutal loss in the 2018 Champions League Final where the goalkeeping was an albatross for the Reds.
It was clear that Liverpool would not be able to simply overwhelm teams with goals. So, they took the massive payday from moving Philippe Coutinho and brought in Fabinho and Alisson.
The Brazliain pair finally gave the Reds the spine they were lacking. Alisson's tremendous shot-stopping ability in combination with his strong skills on the ball meant he was in a rare class of keeper.
He has since gone on to win every trophy possible, score an iconic goal and be considered the best goalie in world football. He has more than returned the favor the fee it took to secure his services. Without him, this dynastic run might have never happened.