Walmart currently has the Xbox 360 version of Assassin's Creed 3 on sale for $14.98. Pre-ordering the game will net you the added "A Dangerous Secret" in-game mission, and $4.99 of credit for the Vudu movie service.
While the low price is probably just a pricing error on the store's part, a deal is a deal, so grab a copy while it lasts.
Assassin's Creed is out on October 31 for Xbox 360 and PlayStation 3, and on November 23 for PC.
UPDATE: Alas, my friends, Walmart has corrected the error. The game is now listed at the standard price of $59.96 again.