public function getTotal()
 {
     $room_price = Room::byId($this->id_room)->price;
     $service_price = $this->id_service > 0 ? Service::byId($this->id_service)->price : 0;
     if ($service_price) {
         $service_price *= $this->adults + $this->childs;
     }
     return $this->getDays() * $room_price + $service_price;
 }
 public function getTotal()
 {
     $price = Room::byId($this->id_room)->price;
     return $this->getDays() * $price;
 }
<?php

require_once 'config.php';
define('ID_LANG', 1);
if (isset($_GET['id'])) {
    $booking = Booking::byId($_GET['id']);
    $user = User::byId($booking->id_user);
    $room = Room::byId($booking->id_room);
    // HEADER
    // create a PDF object
    $pdf = new pdf(PDF_PAGE_ORIENTATION, PDF_UNIT, PDF_PAGE_FORMAT, true, 'UTF-8', false);
    // set document (meta) information
    $pdf->SetCreator(PDF_CREATOR);
    $pdf->SetAuthor('Hotel Plaza Nueva');
    $pdf->SetTitle('Hotel Plaza Nueva');
    $pdf->SetSubject('Hotel Plaza Nueva');
    $pdf->SetKeywords('hotel, plaza, nueva, granada');
    // add a page
    $pdf->AddPage();
    // create address box
    $pdf->CreateTextBox($user->name, 0, 55, 80, 10, 10, 'B');
    $pdf->CreateTextBox($user->email, 0, 60, 80, 10, 10);
    $pdf->CreateTextBox($user->phone, 0, 65, 80, 10, 10);
    //$pdf->CreateTextBox('Zip, city name', 0, 70, 80, 10, 10);
    // invoice title / number
    $pdf->CreateTextBox('Factura #' . $booking->id, 0, 90, 120, 20, 16);
    // date, order ref
    $date = date_create($booking->date_booking);
    $pdf->CreateTextBox('Fecha: ' . date_format($date, "d/m/Y H:i:s"), 0, 100, 0, 10, 10, '', 'R');
    $pdf->CreateTextBox('Order ref.: #' . $booking->id, 0, 105, 0, 10, 10, '', 'R');
    // ROWS