I have a confession: I don´t know how to create a Marketplace with Marketpress!

I need to create a sistem where members sell THEIR products in ONE SITE where everybody can upload their products to sell, is this possible?

If I have 1000 members I wouldn't want them to create 1000 sub-sites.

I have tried several times, but with no avail.

Is Marketpress only formated for each member to create his own store (multisite - the 1000 store model I mention above) and manage it through his WP back-end? If this is so, can there be a way of uploading products on the front-end for each store? (I don´t want to teach users how to use the WP Dashboard).

Thank you and cheers from Buenos Aires,