The seller should be able to add their own products with pictures and info and then I should be able to view them before accepting them.
When a person buy a product the money should go to my account and stay there until the buyer report that the product arrived and then the money should go back to the seller except for 20% which should stay in the company. The website should also have the following features:
Search engine for products
become a seller page where the seller register their info about them and their bank account etc.
A System for me to write newsletters and to manage and design mails that automatically should go to a buyer and the seller.
A special picture viewer where sponsored space could be able to rotate in first page. I should be able to control those spaces and sell that service for sellers who would like to promote their products a little extra.
Info pages which I should be able to control and manage.
Good payment option where client should be able to pay with visa card.
Also a feature about how a new seller could prove that he is he. In sweden we use bank id which you start via your phone and identify yourself with.