build website for receiving orders and currency exchange

About us : We are a startup agency located in Algeria we want to provide a service to make shopping online much easier. What do we need : A website that handles client orders. When the client is signed up he can place an order he must provide the link of the item that he want to buy and the quantity and the price of the product and if he wants to ship it directly or by our address after that the order is placed and waiting for reply we will see the order and reply how much the price if it is OK with the client than we will proceed to the next step buying the product be for we buy he must pay and send a proof of the payment to us, after we check that the payment done then we will buy the item and change the status of the order to completed waiting for the item to be arrived. For each order has his own I'd we will place it on the address of the order. When the original website sends to us the tracking number we will update the status of the order and attache the tracking number. The other service on the website : Currency selling only user who has accepted buy us can sell currency. Any signed up user can buy. A search tab on the top of the website with filter the filter has : Currency kind ( payoneer, PayPal, Paysera,... Etc) those currency can be added buy the seller. Online status. Less then or greater than. The seller profile has his picture name and description and bellow has what hi services or currencyis and also buyers comments and evaluation and the seller badge (this can be added buy the admin) Rating number (100%) and how many time he sold his services 1 or 2 ....