操作需要2位小数

I have this php code and i want this operations to apear with 2 decimals only. After the php code i'll put an example of what i receive on the output.

$Unir_Destino=$_POST['destino']; 
$tons=$_POST['tons'];
$descom=$_POST['descom'];
$remis=$_POST['remis'];
$fact=$_POST['fact'];
mysql_connect("localhost", "user", "password") or die (mysql_error()); 
mysql_select_db("Destinos") or die (mysql_error()); 
$Precio= mysql_query("SELECT Precio FROM Destinos WHERE Destino ='$Unir_Destino'");
$Precio1 = mysql_fetch_array($Precio);
$Precio2 = ($Precio1['Precio']);
$Total = $Precio2 * $tons;
$iva = ($Total / 100) * 16;
$totiva = $Total + $iva;
$rete = ($Total / 100) * 4;
$toret = $totiva - $rete;


        <span style="font-family: Tahoma;">
            <b>Subtotal:</b>       <?php print "$$Total <br />";?>
            <b>IVA:</b>            <?php print "$$iva <br />"; ?>
            <b>Subtotal + IVA:</b> <?php print "$$totiva <br />";?>
            <b>Retencion:</b>      <?php print "$$rete <br />";?>
            <b>Total:</b>          <?php print "$$toret <br />";?>
        </span>

Subtotal: $6297.9 IVA: $1007.664 Subtotal + IVA: $7305.564 Retencion: $251.916 Total: $7053.648

You can use PHP's number_format() method

Reference: http://php.net/manual/en/function.number-format.php

Here's an example taken from the reference:

<?php

$number = 1234.56;

// english notation (default)
$english_format_number = number_format($number);
// 1,235

// French notation
$nombre_format_francais = number_format($number, 2, ',', ' ');
// 1 234,56

$number = 1234.5678;

// english notation without thousands separator
$english_format_number = number_format($number, 2, '.', '');
// 1234.57

?>