if ($advert_sub == 'paypal') {
                $a = array('cmd' => '_xclick',
                           'business' => SITE_PAYPAL_EMAIL,
                           'currency_code' => SITE_CURRENCY,
                           'item_name' => '[Campaign ID: ' . $cid . '] ' . $website_name,
                           'amount' => $subtotal,
                           'notify_url' => SITE_PAYPAL_CALLBACK_URL,
                           'tax_rate' => Utilities::getVAT($subtotal),
                           'custom' => serialize(array('cid'=>$cid)),
                           'image_url' => SITE_PAYPAL_CHECKOUT_LOGO,
                           'cpp_ headerback_ color' => '2687be',
                           'no_shipping' => '1',
                           'return' => SITE_LOCATION . '?done',
                           'cancel_return' => SITE_LOCATION . '?cancelled'
                );
                $u = 'https://www.paypal.com/cgi-bin/webscr?' . Utilities::arrayToURI($a);
                System::redirect($u);
            }