I have a site where I will sell beats online. I purchased the one time download plugin and am aware that all it does is provide protection to download file link. However I notice that once you set up a product in the admin area, it also provides an optional automatic email function where you can add an attachment. So my question is If I set up a product where they can but an mp3 beat, as soon as they make a payment via paypal, can I just simply attach the mp3 file to the default email for that specific product set up?
Considering that email isn't as reliable as we'd like, I wouldn't suggest doing that. Also, some email programs are set up to delete attachments, so if you have a customer with such a program, you need to provide an alternate way of providing access to what they paid for. If you're looking for an easier way to provide download links, you can add the link in the product description, and use .htaccess to ensure that the only people who can download the file are those who have paid for it. This way, your customers can log in and download their purchases right from the members.php page.