I would like to set up a BUY NOW button that requires the buyer to pay for downloading a pdf file--how do you go about setting up the re-directions so that when the buyer clicks on the button, the buyer first pays for the download and only then is directed to a place to download the file.
One method for Digital Downloads is to enable the Auto Return feature in your Account Profile. After a successful transaction, the buyer is immediately sent back to a specific page where they could download the item. Note, using this method, the URL can be shared with others as it is not secure.
Another method would be to use PayPal's IPN feature. This method does require additional programming skills. After the payment is processed, PayPal posts the transaction details to your IPN script. At this point, you could have your IPN script either send out an email with the item as an attachment, or an email that has a link to a secure page where the item can be downloaded from.
I was setting up a web site for this and they directed be to use "click bank" they have a program which talks you thru the process of paying and then down loading so that the customer cant down load without paying.