Note Selling Website

Hi, I need a website which will allow registered users to upload notes or documents (either in pdf or Word format) to be sold. - The proceeds of any sale will be deposited into the user's Paypal account, minus a commission for the site administrator. - All uploaded documents must first be approved by the site administrator before they are published. - The user will be able to track which documents they currently have for sale and basic info such as how many sold, sales so far (by week/month/total)...etc, and manage their account and uploads. - The user will be able to set the price for each document although the site administrator can set a floor limit on prices. - Visitors to the site will be able to ask the seller questions through a simple form on the website (similar to eBay). - The website will produce a sample of the text from the first few pages of the document and display it of the document's description page. I would prefer the website to be developed using the Joomla CMS as a base, however a completely custom PHP website may be acceptable as well.