free_level_remove_pmpro_level_cost_text.php

<?php
/**
 * Remove the level cost text on the checkout page for free levels.
 *
 * 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/
 */
function free_level_remove_pmpro_level_cost_text( $text, $level ) {
	global $pmpro_pages;
	if ( is_page( $pmpro_pages['checkout'] ) && pmpro_isLevelFree( $level ) ) {
		return '';
	} else {
		return $text;
	}
}
add_filter( 'pmpro_level_cost_text', 'free_level_remove_pmpro_level_cost_text', 10, 2 );