With Man Utd, in my second season I was taken over by a tycoon (yes, I nearly bankrupted Man Utd in my first year) and kept as manager I was given a £313M transfer budget.
Since Messi had a minimum fee release clause of roughly £217M I decided to try to sign him. However, my board wouldn't allow me to pay him the requisite loyalty bonus. The yearly wages, agent fees, and incentives were pretty darn exorbitant, too, so I simply decided he wasn't worth it. After all, I could sign four or five players with 175-180 PA's for the same transfer/wage/other fees so that's what I did. But since I was so rich, I quickly lost interest in the fact I had simply bought success so the game got boring and I'm on a different save now.