Web development -- 3

I need a new website. I need you to design and build a landing page. Hello, I am trying to get an idea of a quote of what a site would be like coding a plugin or script like www.opskins.com. If you don't know what it is, its pretty much a market place to sell virtual cs-go skins. So in my project I would need to allow using STEAM API. The site will basically involve trading of CS:GO skins (much like [login to view URL] and [login to view URL]) with real money and "online store credit". Allowing users to submit to sell their own item and cashing out for real money. And for this we need a complete site development or if capable of customizing our current website. You will supply the coding and a simple design like opskins of the frontend and backend of the site. The frontend of the site needs to look and behave much like a regular market shop (ex. [login to view URL]) but needs to use the Steam API to handle the transactions of CS:GO skins. If you can build it on any e-commerce system that would be okay as well such as Woocommerce, Prestashop, Opencart, etc). The backend site needs to be able to handle Steam account bots, which are used to store skins and it must be fully automated (depositing and withdrawing skins as a user).