public function filterComboSetRealPrice($price, $serial) {
        $sels = unserialize($serial);
        if (empty($sels['comboSetId']) || empty($sels['comboSetItems'])) {
            // not a combo-set
            return $price;
        }

        // add modifiers to combo-set total amount
        foreach ($sels['comboSetItems'] as $serial => $item) {
            $price += (int)$item['price'];
        }

        return $price;
    }