[WTB]Secure code(sql injection)

[validium]

Code:

<?php
    $con = mysql_connect("localhost","db user","password");
    if (!$con)
      {
      die('Could not connect: ' . mysql_error());
      }

    mysql_select_db("db_name", $con);

    $sql="INSERT INTO `db_name`.`form` (`bitcoinaddress`, `amountinbtc`, `phonenumber`) VALUES
    ('$_POST[bitcoinaddress]','$_POST[amountinbtc]','$_POST[phonenumber]')";

    if (!mysql_query($sql,$con))
      {
      die('Error: ' . mysql_error());
      }

echo ($_POST['amountinbtc']);

mysql_close($con);
?>

I need someone who can modify this to stop sql injection.

I also need the data to be saved in sessions so that when the user refreshes the page the same data wont be duplicated in the database.

Willing to pay 15$(negotiable) in btc for this as long as it works as needed.

[Parazyd]

There's something in your database that always returns True. You should fix that.

[validium]

There's something in your database that always returns True. You should fix that.

Fixed. Am still looking for someone to do this.