Customize level cost description depending on the date.

custom-level-cost-text.php

<?php 
/**
 *
 * Custom function to add a late fee to the checkout page in Paid Memberships Pro
 *
 * link: TBD
 * 
 * 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/
 * 
 */
//Customize level text cost at checkout
function my_pmpro_level_cost_text($cost, $level) {
	//check if level id is 3
	if( $level->id == "3" ) {
		//Get the today date without year
		$today = date("m-d");
		//Check if the checkout is between 01-01 and 01-30  or 07-01 and 12-31 and apply late fee policies. $95, 95 + 10 or 45 + 10 respectively. Switch
		if( $today >= "01-01" && $today <= "01-30") {
			$cost = "95";
		} else if ( $today >= "01-30" && $today <= "06-30") {
			$cost = "95 plus 10 late fee";
		} else {
			$cost = "95 minus 40 cause is very late";
		}
	}
	return $cost;
}

add_filter("pmpro_level_cost_text", "my_pmpro_level_cost_text", 10, 2);