Maybe the coupon code should be a url? Perhaps via bit.ly/t.co/etc? I think I would perceive an "I have a coupon" checkbox as taunting me just as much as the t

Maybe the coupon code should be a url? Perhaps via bit.ly/t.co/etc? I think I would perceive an "I have a coupon" checkbox as taunting me just as much as the text box.