im doin car rental site where i have set price to each car. i have worked out number of days between dates. i need this multiply two values to get quota

Im doin a car rental site where each car has a set price. I have an orderpage2.php that takes in the pick up date and the drop off date. I have calculated the difference in dates. The next page displaycar.php shows the model, make and transmission and price for each car. I want to show the quoted price for each car. That is the price per day multiplied by the number of days.
The following is the code i used for displaycar.php to get price per day and day difference:

<?php
session_start();
header("Cache-control: private"); //IE 6 fix*/
$pickup = $_POST['pickup'];
$dropoff = $_POST['dropoff'];
$pickupdate = $_POST['Pick_Up_Date'];
$dropoffdate = $_POST['Drop_Off_Date'];
$transmission = $_POST['transmission'];
$_SESSION['pickup'] = $pickup;
$_SESSION['dropoff'] = $dropoff;
$_SESSION['Pick_Up_Date'] = $pickupdate;
$_SESSION['Drop_Off_Date'] = $dropoffdate;
$_SESSION['price'] = $price;
$_SESSION['transmission'] = $transmission;
?>
<?php function makeTimestamp( $date )
{    
static $months = array( 1 => 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec' );  
$fixed = preg_replace('#^\s*(\d{1,2})\s*([-/\.])\s*(\d{1,2})\s*\\2\s*(\d{2,4})\s*$#e', 'sprintf(\'%02d-%s-%04d\', intval(\'\\1\'), $months[intval(\'\\3\')], (strlen(\'\\4\') < 4 ? 1900 : 0) + intval(\'\\4\') )', $date);    
return strtotime($fixed);
}  
function toDays( $timestamp )
{  
  return intval(intval($timestamp) / (24 * 60 * 60));
}
 function dateDiff( $date1, $date2 )
{    $date1 = toDays(makeTimestamp( $date1 ));  
 $date2 = toDays(makeTimestamp( $date2 ));        
return abs($date1 - $date2);
}
echo dateDiff( $pickupdate, $dropoffdate );

?>


I know i wont need to echo datediff. its just how to get price in database, for each car that is available multipiled by datediff.



I just echoed out the differnce in dates to see if it worked. i want to multiply this date difference by the price per day and display it in the price field. But there is small complication on to this. if the datediff = 0 i want the price field to just display the price in the database else if datediff = 1 i want the price to be price in the database + price in the database(price in database * price in database) else if datediff > 1 i want the price in price field to display the price in database * datediff + price in database,
for example if price per day in database = 20 and calculated date diff = 4
price field should hold value of 4*20+20 = 100


the following is the code for printing out the results. i know the last echo wont be echo row['price']. it must be whatever calculation i worked out:

<?
include "db_connection.php";
$connect = db_connect();
if ($connect)
$_SESSION['pickup'] = $pickup;
//$_SESSION['username'] = $username;
{
$query = "select * from car Where pickup ='$pickup' && transmission Like '%$transmission'"; //Selecting all Entries from the database

      $result = mysql_query($query,$connect); //Assigns the variable result to the Query Connection
      
      //$temp = mysql_fetch_array($result);
                  
      if(mysql_num_rows($result)==0)
      {
      
      echo"There are no Records with the location You have entered.";?>        <P>  
          <a href="orderpage.php">
      
      
          <?
      echo"Please Click Back";
      
      }
      
      while($row = mysql_fetch_assoc($result)) //;
      {
        ?>       
          </center>
        
      
      
          <table border="" cellpadding="0" cellspacing="1" style="border-collapse: collapse; border-width: 0" bordercolor="" width="100%" id="AutoNumber6">
            <!--DWLayoutTable-->
            <b>
            <tr>
              <td width="105" height="44" valign="top"><b><a href = "EnterCreditCard.php?model=<? echo $row['Model']?>&make=<? echo $row['Make']?> " ><? echo $row["Model"]; ?>  </a></b></td>
              <td width="116" valign="top"><? echo $row["Make"]; ?></td>
            <td width="112" valign="top"><? echo $row["transmission"]; ?></td>
              <td width="115" valign="top"><? echo $row["price"]; ?></td>
            </tr>
                  
                 <?