Try this...
Code:
{if $product.list_price ne "0"}
<b>{$lng.lbl_list_price}:</b> {$config.General.currency_symbol}{$product.list_price}<br>
<b>{$lng.lbl_price}:</b> {$config.General.currency_symbol}{$product.taxed_price}<br>
<b>{$lng.lbl_save}:</b> {$config.General.currency_symbol}{math equation="x - y" x=$product.list_price y=$product.taxed_price format="%.2f"} !
{/if}