Tracked by Evreward since 2010, bluemercury offers coupons, cash back rebates and rewards, with savings as high as 15% off. bluemercury discount coupons are seasonal, appearing every three to four months, and are often more valuable than similar merchants. Even when bluemercury doesn't have a coupon, you can always get up to 25% cash back, and other great rewards, with every purchase.