An external site is always easier, but they tend to take a cut of your profits. If you can handle some basic programming, PayPal has IPN (Instant Payment Notif

An external site is always easier, but they tend to take a cut of your profits. If you can handle some basic programming, PayPal has IPN (Instant Payment Notification) in which PayPal will load a specific file on your server passing it info about the completed/failed payment. You can very easily use data that to allow the buyer access to files. Full details here - https://www.paypal.com/ipn https://www.paypal.com/ipn