CModule::IncludeModule("iblock");
    CModule::IncludeModule("catalog");


    $arSelect = Array(
        "ID", "IBLOCK_ID"
    );
    $arFilter = Array("IBLOCK_ID" => 12, "!PROPERTY_CML2_ARTICLE" => false);
    $res = CIBlockElement::GetList(Array("ID" => "DESC"), $arFilter, false, false, $arSelect);
    // Проход по всем товарам
    while ($fields = $res->GetNext()) {

        // Вытащить цену у данного товара
        $resPrice = CPrice::GetList(
            array("ID" => "ASC"),
            array(
                "PRODUCT_ID" => $fields["ID"],
                "CATALOG_GROUP_ID" => 3
            ),
            false,
            array("nTopCount" => 1),
            array("ID", "PRODUCT_ID", "PRICE")
        );
        if ($price = $resPrice->Fetch()) {

            // Установить свойство с ценой для расчёта скидки
            CIBlockElement::SetPropertyValueCode($fields['ID'], 'INT_FOR_DISCOUNT', $price["PRICE"]);
            /*CPrice::Update(
                $price["ID"],
                array(
                    "PRODUCT_ID" => $offer["ID"], "CATALOG_GROUP_ID" => $arFields["CATALOG_GROUP_ID"],
                    "PRICE" => $arFields["PRICE"], "CURRENCY" => $arFields["CURRENCY"]
                )
            );*/
        }

    }