Anyone have a recommendations for a Local Market Website?

Hi guys and gals,

I'm wondering about the way to go about creating a website for a Local Market.
We want to have a special section or page for each merchant.
We would also wish to have the ability for each merchant to allow purchases managed through him alone. (Not through the Umbrella...)
I have a membership and I know WPMU has a lot of excellent plugins, but I'm trying to avoid wasting time learning all these different plugins if I can focus on one or two that you recommend.

Thank You