Dynamically create a HTML document, that stores a "key" cookie on the client. Create the cookie in such a way that you "never" will get the same cookie again and that the client can not figure out what someone else's cookie would be by simple means. In other words, security through obscurity.
Associate a cookie with a file or data base entry on the host.
If a cookie already exists on the client continue to use it, don't create a new one.
Provide a "result" or "buy" page that displays the combined content of the users data file.
As with the forms topic please talk to me before starting this one. It never hurts to do something that is actually useful to someone.