I can't find the Authentic Landry from NFL shop so heres a Taylor:
1st the knock off:

Now the $284.99 from sportsauthority:
The sleeves are definitely fishy. The bands of colors on the authentic seem to be wider and closer to the elastic. Like Matty once said, "The only one that cares about your jersey is you." I cared so much I bought both an authentic 70th anniversary serially numbered Darrell Green jersey, and last year I bought the authentic Riggins jersey. I personally prefer the real ones.