Tracked by Evreward since 2006, Boston Proper offers coupons, cash back rebates and rewards, with savings as high as 75% off. Boston Proper discount coupons are somehwat rare, available a few times each year, and can be less valuable than similar merchants. Even when Boston Proper doesn't have a coupon, you can always get up to 18% cash back, and other great rewards, with every purchase.