public function cost($to, $text) 
    {
        $url = self::HOST . self::COST;
        $this->id = null;

        $params = $this->get_default_params();
        $params['to'] = $to;
        $params['text'] = $text;

        $result = $this->request($url, $params);
        $result = explode("\n", $result);

        return array(
            'code' => $result[0],
            'price' => $result[1],
            'number' => $result[2]
        );
    }