[B00MER]

...And if are running an older version of X-cart less than version 3.3.8:

Save the following code to Smarty-2.1.1/plugins/function.random.php.

Note your Smarty-2.1.1 directory may differ.

<?
	/*
	 * Smarty plugin
	 * -------------------------------------------------------------
	 * File:     function.random.php
	 * Type:     function
	 * Name:     random
	 * Author:   Ben Godfrey <ben@hypothetical.co.uk>
	 * Purpose:  outputs a random number in the range specified 
by min and max attribs or 0 and mt_randmax
	 * Usage:    {random min=0 max=10}, {random min=-10}, 
{random max=20} or just {random}
	 * -------------------------------------------------------------
	 */

	function smarty_function_random($params, &$smarty) {
		extract($params);

		if (empty($min)) $min = 0;
		if (empty($max)) $max = mt_getrandmax();

		// complain about erroneous args
		if (!is_numeric($min)) {
			$smarty->trigger_error("random: parameter 'min' must be a number");
			return;
		}
		if (!is_numeric($max)) {
			$smarty->trigger_error("random: parameter 'max' must be a number");
			return;
		}

		print(mt_rand(floor($min), ceil($max)));
	}

	// initialise random number sequence
	mt_srand(time());
?>

How to use it in .tpls?

{random min=0 max=10}, {random min=-10},  {random max=20} or just {random}

Kudos!