Zavvi offers The Ultimate Gangster Blu-ray Box Set
(£7.99) plus $2.46
for shipping (£1.99). That's the lowest total price we could find by $4. It includes American Gangster, Carlito's Way, Casino, Public Enemies, and Scarface.
Note: This Blu-ray set is region-free; it will play on U.S. Blu-ray players, but the extras and special features may not.
Of note, new customers can apply coupon code "WELCOME" to cut the price to $8.88.