You would still need your own server back-end logic to process the data that Essentials would send to it. Keep in mind with the inherent limitation of the socket system you're limited to only an HTTP connection. I have a video which goes over how to use the script end-points of the Sockets and how to write minor server logic in PHP which may be useful:
If you want to create a feature like trading, you need some sort of persistent data store on your server as well. So either a relational database, or whatever other data store you think would be easiest (MySQL is provided by a lot of Apache based webhosts, so using PHP and MySQL to create the online functionality is usually the easiest approach).