I need to make website with the following feature
1- user login to upload files with specific extensions
2- user put price to each of his files.
3- user choose the payment method he likes
4- website owner get % of that price when any visitor buy this item
5- user can tweet or share this document in his page
6- there will be Facebook commenting tool ..
7- user can choose which category he will put his file IN
8- it will be great if there is something like blog to add articles.
I need open source .
appropriated low price and sample of work would be great