Discounts the price of a membership by $50 when a user pays by check using Paid Memberships Pro and PMPro Pay by Check Add-On. For use in PMPro Customizations Plugin.

discount_with_check.php

<?php


/**
 * If a user paid by check, give them a $50 discount.
 */
function my_pmpro_discount_with_check( $level ) {
	if ( 'check' === $_REQUEST['gateway'] ) {
		$level->initial_payment = $level->initial_payment - 50;
		// $level->billing_amount = $level->billing_amount - 50;	//to update recurring payments too
	}

	return $level;
}
add_filter( 'pmpro_checkout_level', 'my_pmpro_discount_with_check' );