Is there a way to make a page "expire" after the person has left the page? For example, I'm creating a site for a producer who is selling tracks/beats on his site, the customer agrees/disagree to the terms and condition & proceeds to pay for track (through paypal button) & is redirected from paypal to the download link for this track. But once they leave the download page they can't just hit the "back" button or bookmark the page. I want a message saying "page expired or error" or whatever. Is that possible? pretty much like password protecting the page w/out a password protect lol. Hope this made sense.

I'm thinking it has something to do w/tracking ip addresses or enabling cookies or whatever. I don't know, but I need help.

I know there is an addon for this but I don't have the money for this particular project to purchase concrete5 ecommerce & then purchase the digital download addon. (a favor for a friend, will be making money THROUGH him tho, hopefully purchase the addon soon).