function calc_net_price($price)
{
	$limitz = array(1000,	5000,	... );
	$multiz = array(1.5,	1.35,	... );

	$price /= 1.27;
	for ($i = 0; $i < count($limitz); ++$i)
	{
		$chk = $price / $multiz[$i];
		if ($chk < $limitz[$i])
		{
			return $chk;
		}
	}
}