Calcule d'un TTC sur bon de commande

<form action="envoi.php" method="post" name="form_contacts" id="form_contacts">
  Monsieur <input name="sex" value="Monsieur" id="sex" type="radio">
  Madame <input name="sex" value="madame" id="sex" type="radio"> </p>
 
  <p align="left">Nom : <input name="nom" id="nom" type="text"> </p>
 
  <p  align="left">Pr&eacute;nom
: <input name="prenom" id="prenom" type="text">
  </p>
 
 
  <p  align="left"><span style="font-size: 12pt; font-family: &quot;Times New Roman&quot;,&quot;serif&quot;;">Adresse</span><span style="font-size: 12pt; font-family: &quot;Times New Roman&quot;,&quot;serif&quot;;">
  </span> <input name="adresse" id="adresse" type="text"><br>
  </p>
  <p  align="left">Ville
  <input name="npa" id="npa" type="text">&nbsp;Code
postal </span> : <input name="localite" id="localite"></p>
 
  <p  align="left">T&eacute;l</span>:
  <input name="tel" id="numtel" type="text">
Fax </span> <input name="nat" id="nat" type="text"> </p>
 
  <p align="left"><span >adresse
email : <input name="email" id="email" size="50" type="text"> </span></p>
  <br>
  <br>
  <table style="text-align: left; width: 70%;" border="0" cellpadding="2" cellspacing="2">
    <tbody>
      <tr>
        <td style="text-align: center; vertical-align: top;">&nbsp;</td>
        <td style="text-align: center; vertical-align: top;"><b><span style="font-size: 10pt; font-family: &quot;Arial&quot;,&quot;sans-serif&quot;;">R&eacute;f&eacute;rence</span></b></td>
        <td style="text-align: center; vertical-align: top;"><b><span style="font-size: 10pt; font-family: &quot;Arial&quot;,&quot;sans-serif&quot;;">Quantit&eacute;</span></b></td>
        <td style="text-align: center; vertical-align: top;">PRIX</td>
      </tr>
      <tr>
        <td style="text-align: center; vertical-align: top;">&nbsp;</td>
        <td style="text-align: center; vertical-align: top;"><span ><input name="commande" id="commande" size="50"></span></td>
        <td style="text-align: center; vertical-align: top;"><span ><input name="nombre" id="nombre" size="50"></span></td>
        <td style="text-align: center; vertical-align: top;"><input name="prix" id="prix" size="10" /></td>
      </tr>
      <tr>
        <td style="text-align: center; vertical-align: top;">&nbsp;</td>
        <td style="text-align: center; vertical-align: top;"><span >
          <input name="commande2" id="commande2" size="50" />
        </span></td>
        <td style="text-align: center; vertical-align: top;"><span ><input name="nombre2" id="nombre2" size="50"></span></td>
        <td style="text-align: center; vertical-align: top;">&nbsp;</td>
      </tr>
      <tr>
        <td style="text-align: center; vertical-align: top;">&nbsp;</td>
        <td style="text-align: center; vertical-align: top;"><span ><input name="commande3" id="commande3" size="50"></span></td>
        <td style="text-align: center; vertical-align: top;"><span ><input name="nombre3" id="nombre3" size="50"></span></td>
        <td style="text-align: center; vertical-align: top;">&nbsp;</td>
      </tr>
      <tr>
        <td style="text-align: center; vertical-align: top;"><input type="image" name="imageField" id="imageField" src="arrow_black_1.gif" /></td>
        <td style="text-align: center; vertical-align: top;"><input name="commande4" type="text" id="commande4" value="pamilles" size="50" />          </span></td>
        <td style="text-align: center; vertical-align: top;"><span ><input name="nombre4" id="nombre4" size="50"></span></td>
        <td style="text-align: center; vertical-align: top;">&nbsp;</td>
      </tr>
      </tbody>
  </table>
  <br>

  <br>
 
  <p align="left"> <input type="submit" value="envoyer"> <input name="retablir" id="retablir" value="R&eacute;tablir" type="reset"> </p>
 
</form>
 

<?php
 
 
//On récupère les valeurs du formulaire
$nomembre = $_POST['nomembre'];
$sex = $_POST['sex'];
$nom = $_POST['nom'];
$prenom = $_POST['prenom'];
$jour = $_POST['jour'];
$mois = $_POST['mois'];
$annee = $_POST['annee'];
$adresse = $_POST['adresse'];
$npa = $_POST['npa'];
$localite = $_POST['localite'];                                                          
$tel = $_POST['tel'];  
$nat = $_POST['nat'];
$email = $_POST['email'];
$commande = $_POST['commande'];
$nombre = $_POST['nombre'];
$prix = $_POST['prix'];
$commande2 = $_POST['commande2'];
$nombre2 = $_POST['nombre2'];
$commande3 = $_POST['commande3'];
$nombre3 = $_POST['nombre3'];
$commande4 = $_POST['commande4'];
$nombre4 = $_POST['nombre4']; 
 
?>
<?php //On créée le message email
 
$msg = "Civilité : ". $sex ."\r\n";
$msg .= "Nom : ". $nom ."\r\n";
$msg .= "Prénom : ". $prenom ."\r\n";
$msg .= "Adresse : ". $adresse ."\r\n";
$msg .= "Ville : ". $npa ."\r\n";
$msg .= "Code postal : ". $localite ."\r\n";
$msg .= "Télephone : ". $tel ."\r\n";
$msg .= "Fax : ". $nat ."\r\n";
$msg .= "Adresse email : ". $email ."\r\n";
$msg .= "Référence : ". $commande ."\r\n";
$msg .= "Quantité : ". $nombre ."\r\n";
$msg .= "Prix : ". $prix ."\r\n";
$msg .= "Référence2 : ". $commande2 ."\r\n";
$msg .= "Quantité2 : ". $nombre2 ."\r\n";
$msg .= "Référence3 : ". $commande3 ."\r\n";
$msg .= "Quantité3 : ". $nombre3 ."\r\n";
$msg .= "papilles : ". $commande4 ."\r\n";
$msg .= "Quantité 4 : ". $nombre4 ."\r\n";
 
 
 
 
$recipient = "florinda_2@hotmail.fr"; //On met l'adresse email ou on veut recevoire le mail
$subject = "bon de commande"; //On met le sujet du mail
 
$mailheaders = "From: ".$email."<".$email.">\r\n";
$mailheaders .= "X-Sender: ".$email."\r\n";
$mailheaders .= "X-Mailer: PHP/".phpversion()."\r\n";
$mailheaders .= "X-Priority: 2\r\n";
$mailheaders .= "Return-Path: ".$email."\r\n";
$mailheaders .= "MIME-Version: 1.0\r\n";
$mailheaders .= "Content-Type: text/plain; charset=\"US-ASCII\"\r\n";
$mailheaders .= "Content-Transfer-Encoding: 7bit\r\n";
 
 
mail($recipient, $subject, $msg, $mailheaders); // message confirmation que le mail a bien été envoyé
 
echo "<HTML><HEAD>";
echo "<TITLE>Inscription envoyer!</TITLE></HEAD><BODY>";
echo "<H1 align=center>Merci, $sex $nom $prenom </H1>";
echo "<P align=center>";
echo "La commande a bien été transmis, et nous vous en remercions.<br>Je vais y donner suite dans les meilleurs délais.<br>A bientôt.</P>";
echo "</BODY></HTML>";
 
?><?php

?>