Tracked by Evreward since 2011, HalloweenCostumes.com offers coupons, cash back rebates and rewards, with savings as high as 30% off. HalloweenCostumes.com discount coupons are rare. Even when HalloweenCostumes.com doesn't have a coupon, you can always get up to 15% cash back, and other great rewards, with every purchase.