Use BuyCostumes coupon code EXTRA30
BuyCostumes has this Assassin's Creed Brotherhood Adult Costume for $99.99. Use the coupon code and the price drops to $69.99. It's available in sizes S to L. Plus, after you buy it you can do stuff like THIS
without looking ridiculous. Target
has the same item for $134.99. Shipping is $4.99.