简单的PHP - 做数学和用PHP显示答案？

I am in Opencart and trying to display a price that has been divided by 1000 then times by 38. I have two files, product.php and product.tpl The tpl file is the front end and php file is the back end.

In the php file I have:

                if($special>0){
                    $lease_price = (($special/1000)*38);
                    } else {
                    $lease_price = (($price/1000)*38);
                    }
                    $lease_price = $this->currency->format($lease_price);

and in the tpl file I have:

                    <p>
                        <i class="fa fa-chevron-down"></i>
                        <b>Lease To Buy Price:</b>
                        <span><?php if($price>500){ ?>
          <?php echo $lease_price; ?>
          <?php } else { echo 'NA'; } ?></span>                     
                    </p>    

The $special tag is the price of the product when on offer and the $price tag is the normal price.

Here's the page I'm trying to implement this on: http://www.framec.co.uk/index.php?route=product/product&product_id=50

This doesn't seem to work; it only shows NA. Does anyone know what could be the issue here? Thanks :)