(via Jim Callis, on the MLB Network during the draft)
Aiken has apparently agreed to a $6.5M contract. Largest bonus ever for a high school pitcher.
The other important figure is that this bonus is approximately $1.3 million under slot (although $1.4 million was the under-slot figure quoted on the MLB network).
Correction - if he signed for 6.5 million, it would be 1.4 million under slot. My bad.