Notice: Undefined variable: id in PHP

Do this, and it will work:

if ($amount) {
                $host = 'localhost';
                $user = 'root';
                $pass = '';
                $db = 'deedok';
                $connection = mysqli_connect($host, $user, $pass, $db);
                echo 'connected_deedok';
                if (!$conn){
                    die('Database Connection Lost.');
                }
                    $query_deedok = "SELECT * FROM products WHERE amount='" .  $amount . "'";
                        $query_deedok_result = mysqli_query($connection, $query_deedok);
                if ($query_deedok_result != NULL) {
                    while($query_deedok_result_rows = mysqli_fetch_assoc($query_deedok_result)) {
                        $name = $query_deedok_result_rows['name'];
                        $id = $query_deedok_result_rows['id'];
                        $description = $query_deedok_result_rows['description'];
                    }
                        }
        echo $name;
        echo $id;
        echo $description;
            }

Your $amount variable is not parsed and will not be replaced with the assigned value as you have included it in quotes.