Hi, Im just wondering if this is possible with Zen Cart?

I am wanting to make a site where customers can put their own items up for sale, you know like on Ebay how you list your own items. It would also be good if I could keep track of what each user has listed, so I can add up how many items each person is listing.

Would that be possible and how would I go about it? i dont mind using an add-on as long as its not a very expensive one, if you know of one that could help please let me know.

Have I been clear enough in my explanation?...
Thanks for your help!