Sorry I chopped off the mail() function - here is the full code. Yes I can see I might need a 'while' loop but I'm not quite sure how best to do this with this code, any help would be appreciated. Here is the full code:
// This code is activated monthly via cron job and sends out a reminder for payment of service.
require_once('../mysql_con.php'); // database connection
$query = "SELECT price, email, company, name FROM invoice"; // selecting information from db
$result = mysql_query($query); // getting the results of the query
$row = mysql_fetch_assoc($result); // putting the results into a variable
// Set up the email variables
$from = "support@mrwebfix.com";
$to = $row['email'];
$subject = "Invoice";
$body = "<h1>To " . $row['company']. "</h1> Dear " . $row['name'] . "<br />Thank you for choosing <strong>me</strong> as your service provider, the following payment " . $row['price'] . " is now due.<br />Payment within 14 days would be greatly appreciated.<p> Kind Regards.</p>";
mail($to, $subject, $body)