pmpro-additional-fees-checkbox.php

<?php 
/**
 * This recipe will add additional fees and pricing
 * 
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
 
 //we have to put everything in a function called on init, so we are sure Register Helper is loaded
 function my_pmprorh_init()
 {
     //don't break if Register Helper is not loaded
     if(!function_exists( 'pmprorh_add_registration_field' )) {
         return false;
     }
     $fields[] = new PMProRH_Field(
         'addon_options', // input field name, used as meta key
         'checkbox_grouped',         // field type
         array(
             'label'          => 'Choose your selection',
             'options'        => array(      // display the different options, no need for a "blank" option
                 'add_on_a' => 'I would like to receive paper copies of JLS: US $20',
                 'add_on_b' => 'I would like to receive paper copies of ijCSCL: US $20',
             ),
             'profile'        => true,
             'memberslistcsv' => true,
             'addmember'      => true,
             'required'       => false,
         )
     );
     //add the fields into a new checkout_boxes are of the checkout page
     foreach($fields as $field)
         pmprorh_add_registration_field(
             'checkout_boxes',			// location on checkout page
             $field						// PMProRH_Field object
         );
     //that's it. see the PMPro Register Helper readme for more information and examples.
 }
 add_action( 'init', 'my_pmprorh_init' );
 
function my_pmpro_checkout_level($level)
 {
$addon_checkboxes = !empty( $_REQUEST['addon_options'] ) ? $_REQUEST['addon_options'] : '';
if ( ! is_array( $addon_checkboxes ) ) {
   return $level;
}
foreach( $addon_checkboxes as $options ) {
    switch( $options ) {
        case "add_on_a":
            $level->initial_payment = $level->initial_payment + 20; //to update the initial payment.
            //$level->billing_amount = $level->billing_amount + 49;	//to update recurring payments too
        break;
        case "add_on_b":
            $level->initial_payment = $level->initial_payment + 20; //to update the initial payment.
         //$level->billing_amount = $level->billing_amount + 99;	//to update recurring payments too
        break;
    }
}
   return $level;
 }
 add_filter( 'pmpro_checkout_level', 'my_pmpro_checkout_level' );