source.php

<?php
	function freebie () {

		if ( $this->Cart->orderisfree() ) {
			$this->processor = 'FreeOrder';
			$this->processor($this->processor);
			$this->Billing->cardtype = __('Free Order','Shopp');
		} elseif ( 'FreeOrder' == $this->processor ) {
			// If the order is not free, but the order processor is still set to free order,
			// reset the processor to use the default
			return $this->processor = false;
		} else return false;

		return true;
	}