I've been coding for about 3hours i can't seem to see whats wrong, all help is much appreciated! :)

<form method = "get" action = "SLAP2.php">

	$images = array('2010 BMW M6.jpg','2011 BMW 750 Li.jpg','2009 BMW M5.jpg','2010 BMW 650 i.jpg','2010 BMW X6 ActiveHybrid.jpg','2010 BMW 550 I 

G.jpg','2011 BMW X6 xDrive50i.jpg','2011 BMW X6 xDrive50i.jpg','2011 BMW X5 xDrive50i.jpg');

for($x=0; $x<3; $x++) 
			echo '<tr>';
			for($y=$x*3; $y<(($x+1)*3) ; $y++)
				echo '<td align="center"><img src="';
  				echo $images[$y];
				echo '" width="150" height="150">';
				$s = $images[$y];
				$snew = substr($s,0,-4);
				echo '<br>';
				echo '<input type = "checkbox" name = "num[]" value = <?php echo $snew;?> >';
				echo 'Add to cart <br>';
				echo '</td>';
echo '<center><input type = "submit" name = "submit" value = "ORDER"></center>';


echo 'Order list: ';
$prod = $_GET['num'];

foreach($prod as $car)
	echo $car.'<br>';

Not sure what you want to do, and where your problem lies. The only thing I can see from this code, is that line 25 is wrong. The <?php code tag in the echo will not work. You can do this:

echo '<input type = "checkbox" name = "num[]" value = "' . $snew . '" >';

sory for the late reply., thanks pritaeas!