Thats a tough call. You can make the creases go away, but it is retarded that they had to fold it just to keep shipping costs down. I dont think its worth $30 just so its straight when you get it. I think you can straighten it out good enough when you get it and then save the $30.
I also used more screws (about every 4") into the bumper to keep it nice and flush. That helped a lot too