The WB Shop offers The Dark Knight Trilogy Limited-Edition Blu-ray Gift Set bundled with The Dark Knight Trilogy: Ultimate Collector's Edition Memorabilia Pack for $39.98. Coupon code "ANYCODES5" cuts the price to $34.98. With free shipping, that's only $3 more than the lowest total price we could find for the movies alone. It includes Batman Begins, The Dark Knight, and The Dark Knight Rises as well as an artbook, three Mattel Hot Wheels vehicles, and art cards.
Retailers mark up products by hundreds of times their cost — but you don't have to pay the premium.