Converting ColdFusion CFIF to PHP IF statement

OK...I have another one that I am having a problem with.

We offer our standard envelopes for free. So...

If there is a charge in the envelope column that is greater than zero "> 0", I want it to display the charge.
If the column is equal to zero "== 0" , I want it to display the word "FREE"

So here is what I have:
<?php
if ($CardCart->TotalColumn("EnvUpgrade") > 0) {
?>

<?php echo WA_eCart_DisplayMoney($GCcart, $GCcart->DisplayInfo("EnvUpgrade")); ?>

<?php
} else {
?>

FREE
<?php
}
?>


But it gives me this error:
Fatal error: Call to a member function TotalColumn() on a non-object in C:\xampp\htdocs\IndustryGreetings\shopping_cart.php on line 436

line 436 reads:
if ($CardCart->TotalColumn("EnvUpgrade") > 0) {


Thanks!

Grant