Open the site to the public for free in PHP?

I work on a streaming video platform with the CMS called VideoFlix, I'm new to PHP and I hope to have your support to open the site to the general public.

The system works very similar to Netflix, you register, you pay through Paypal and you enjoy content, however I want to eliminate the payment part of the equation so that you only register and ready to enjoy it for the time being. the service to test form.

I found the file that is in charge of the payment through PayPal I want to know that I can modify to obtain this, already try of several forms and none works.

Thank you in advance for your help.

I really hope you help me and not only qualify me with -1 since they did it before and they never helped me.

Payments.php

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Payment extends CI_Controller {

    // constructor
    function __construct()
    {
        parent::__construct();
        $this->load->database();
        $this->load->library('session');
    }

    function paypal_payment($task = '')
    {
        if ($task == 'paypal_post')
        {
            $plan_id        =   $this->input->post('plan_id');
            $user_id        =   $this->session->userdata('user_id');

            $item_name      =   $this->db->get_where('plan', array('plan_id'=>$plan_id))->row()->name;
            $amount         =   $this->db->get_where('plan', array('plan_id'=>$plan_id))->row()->price;
            $custom         =   'plan_id='.$plan_id.'&user_id='.$user_id;
            $business       =   $this->db->get_where('settings',array('type'=>'paypal_merchant_email'))->row()->description;
            $notify_url     =   base_url() . 'index.php?payment/paypal_payment/paypal_ipn';
            $cancel_return  =   base_url() . 'index.php?payment/paypal_payment/paypal_cancel';
            $return         =   base_url() . 'index.php?payment/paypal_payment/paypal_success';

            $this->paypal->add_field('rm',              2);
            $this->paypal->add_field('no_note',         0);
            $this->paypal->add_field('item_name',       $item_name);
            $this->paypal->add_field('amount',          $amount);
            $this->paypal->add_field('custom',          $custom);
            $this->paypal->add_field('business',        $business);
            $this->paypal->add_field('notify_url',      $notify_url);
            $this->paypal->add_field('cancel_return',   $cancel_return);
            $this->paypal->add_field('return',          $return);


            $this->paypal->submit_paypal_post();
        }

        else if ($task == 'paypal_ipn')
        {
            if ($this->paypal->validate_ipn() == false) 
            {
                $ipn_response = '';
                foreach ($_POST as $key => $value) {
                    $value = urlencode(stripslashes($value));
                    $ipn_response .= "\n$key=$value";
                }

                $custom =   $_POST['custom'];
                parse_str($custom,$_MYVAR);
                $data['plan_id']            =   $_MYVAR['plan_id'];
                $data['user_id']            =   $_MYVAR['user_id'];

                $data['paid_amount']        =   $this->db->get_where('plan', array('plan_id'=>$_MYVAR['plan_id']))->row()->price;
                $data['payment_timestamp']  =   strtotime(date("Y-m-d H:i:s"));
                $data['timestamp_from']     =   strtotime(date("Y-m-d H:i:s"));
                $data['timestamp_to']       =   strtotime('+30 days', $data['timestamp_from']);
                $data['payment_method']     =   'paypal';
                $data['payment_details']    =   $ipn_response;
                $data['status']             =   1;

                $this->db->insert('subscription' , $data);
            }
        }

        else if ($task == 'paypal_cancel')
        {
            $this->session->set_flashdata('payment_status', 'cancelled');
            redirect(base_url().'index.php?browse/youraccount' , 'refresh');
        }

        else if ($task == 'paypal_success')
        {
            $this->session->set_flashdata('payment_status', 'success');
            redirect(base_url().'index.php?browse/youraccount' , 'refresh');
        }

    }



}