Phpb2b is an excellent open source back to back business script that gives you a fully functional Alibaba type store straight out of the box!
Installation is easy too, simply upload to your web root and go to yoursite.tld/install/install.php in your browser. You should have set up a database and username prior to this in your hosting control panel. Then just fill in the required info and you're done!
During the installation process you can opt to have sample data installed in order to help familiarise yourself with the content and how to manage it, and you can always get help from their repository at github: https://github.com/ulinke/phpb2b/issues
Upon installation you will get two separate log in's, one for admin and one for the business room.
The business room allows you to sel your own products etc, and admin gives you the ability to adjust your system settings and administrate the site and users.
If you chose to install sample data, you'll find all sections of the site including admin, pre-filled with data, and don't be surprised to find a lot of it written in Chinese, this superstore is after all a Chinese script originally.
All in all you'll find phpb2b to be a well made script and if you're handy with templating you'll find it easy to change it's appearance, or check their templates at github: https://github.com/ualink/phpb2b/tree/master/templates
Or else do a google search.
To run in a production environment, it installs easily on shared hosting but would be best off on a dedciated server, but check the server requirements file or install instructions first.
The only demo I could find is in Chinese, but it will give you a good idea of what the site looks like: http://demo.phpb2b.com/cn5/