Установить цену товару через API

$res = CPrice::GetList(
               array(),
               array(
                     "PRODUCT_ID" => $arItem["ID"],
                     "CATALOG_GROUP_ID" => 3
                  )
               );

               $arFields=array('PRODUCT_ID'=>$arItem["ID"],'CATALOG_GORUP_ID'=>3,'PRICE'=>rand(15,20000),'CURRENCY'=>'RUB', "EXTRA_ID" => '');
               
            if ($arr = $res->Fetch())
            {

               CPrice::Update($arr["ID"], $arFields);

            }
            else
            {$obPrice = new CPrice();
               
               $obPrice->Add($arFields);
            }