create a buying and selling web site

I wish to create a site where people can list their items up for sale and others can purchase the items. The seller and buyer will each have to create an account (user name & password) in order to sell & purchase. The seller will be able to upload a item to the site by filling out a small form (title, description, shipping fee and upload up to 3 pictures). The buyer will be able to see the item and have a option to purchase the item by filling out a small form (mainly the shipping address) and when he makes the purchase he has to pay via paypal, and this payment option should be embedded in the site. the buyer will also have a option to contact the seller for questions regarding item. Each listing should have a unique number (7-8 digits) which the system should automatically create. The home page should look like [login to view URL] (the center part, not the top and sides) . there should be a search option on the top middle part and on the left side there should be different catagories (i.e. electronics, toys, furniture). There should also be a option for seller and buyer to leave each other feedback after the transaction is finished.