Paid downloads with user registration

I provide: - the layout (html+css+graphics) HERE IS WHAT MY WEBSITE NEEDS TO BE CAPABLE OF DOING: Non-registerd users: - can see the full list of files available for download - in order to download a file they need to create an account and purchase credits (single, 10-pack, 20-pack, etc.) This would be done via PayPal preferably, but needs to be seamlessly integrated into the website - no navigating away to [login to view URL]! - a user can also choose a "1 Free Credit" which of course gives him/her 1 free credit to use towards the download - the user still needs to provide his/her credit info to avoid abuse. Registered users: can log into the site with username and password and use their credits to download files (1 credit/file DOWNLOAD). If they want to download the same file at a later time a credit will be used - this is to avoid sharing accounts between people. When a user comes to the site: - sees a list of files available for download (pulled from the DB) -(s)he can click on any of the files to see more details (pulled from the DB) - on the list as well as on the "more details" page a "Download" link for particular file is displayed - if the user is not logged in go to registration page, if the user is logged in allow direct download (use 1 credit). ADDITIONAL INFO: files will be stored with names such as 8123.8182 which is the reference stored in the DB. Once clicked on a download for say [My Music File MP3] the php script needs to rename 8123.8182 on the fly and serve it to the client as [login to view URL] -> this is used just so a simple directory listing on the server won't reveal the content (not even filetype). Here is a minimal list of files that need to be created upon completion of this project: - [login to view URL] <- shows the entire list of files available (needs to be sortable by names), this page also has a searchbox that can be used to find a particular movie - [login to view URL] <- displays the more detailed information on the file - [login to view URL] <- user logs in using this website - [login to view URL] <- user registers a new account here, also buys the credits - [login to view URL] <- page for already registered users to "fill up" their account with more credits - [login to view URL] <- this page has to provide the following functionality: <> add/remove/edit existing file's info (no need to upload the main file, just control the MySQL entries -> this also means upload of small JPGs that are displayed on the file list and "more info" page) <> add/remove/disactivate/activate user <> add/remove credits to any of the users ===================================================== A word document containing the MySQL DBs required is attached. I realize that this sketch might be unorganized and not fully understandable, but this is my first attempt of communicating a project of this sort. Contact me directly with any questions/clarification requests - [login to view URL][at]gmail[dot]com with "Paid downloads with user registration" in the subject line. P.S. Experience with full PayPal integration a big asset!