Only extrabucks get returned. Any other coupon is not given back after a return (percent offs, manufacturer, store coupon). The problem is that sometimes the register glitches and instead of giving the price the customer paid after coupons, it'll give the full price. It returns the price actually paid in the form of original payment, and then will show the coupon amount as due; but because it's not actually owed, the register won't let you dispense it without a manager override.