Corsair packs the Carbide 300R in the same type of brown cardboard box as all of its other enclosures. You will find an image of the chassis in the front, with a blow-up diagram in the rear of the package. Both sides are identical, with two more images and a detailed list of specifications. It seems like most manufacturers are going for simpler packaging, which makes sense, as most people will buy their chassis based on features, specs or price - not because of a colorful box.
The Carbide 300R is held in place by two fairly large Styrofoam spacers. A plastic bag further protects the enclosure from scratches and smudges at the factory.
You will get a basic set of extras with the 300R. A few zip ties and four separate bags of all-black screws along with a manual makes up the accessories. For a case of this price range, just as you would expect.