Best Buy offers Call of Duty: Black Ops II with Revolution Map Pack for Xbox 360 for $14.99. Choose in-store pickup to dodge the $2.99 shipping fee. That's the lowest price we could find by $13.
Of note: Amazon offers the PlayStation 3 version for the same price with free shipping for Prime members. (Non-members can spend $35 to qualify for free shipping; otherwise, it costs $4.98.) That's the lowest total price we could find by $3.