The official opening weekend box office take for Red Tails was, according to Box Office Mojo... $18,782,154.
And the person that came the closest to the number without going over is... Johnnie MD, who guessed $18.6 million. Look at how close...
So, Johnnie MD, email me at firstname.lastname@example.org from the same email address you used when you posted your guess, and I'll get you your $50 Amazon.com gift certificate.
The full list of guesses can be seen HERE.