PHP-KeyCodes now has free button facility

PHP-KeyCodes can automatically send out pin or license key codes after payment from PayPal.

It now has a feature that allows you to send a code to a customer without them making a payment.

The customer enters their email address and the next key code is sent.

You then have a list of customers in your database which you can extract and use for marketing purposes.

For a full description of PHP-KeyCodes refer to http://www.withinweb.com/phpkeycodes