He's 20 million due to his age, 29 is peak age for a footballer after this it's generally downhill, even more so because he relies on his pace. I just don't get this signing to be honest, it'd be different if we already had a goalscorer, but we don't and yet this is the guy we put our faith in, a guy with an overall average record.
Let me also remind you Man City paid 20 million for Gundogan.