allow members to post special offers

Hi all

I would like to offer members the option to post time-sensitive special offers to the community.

I plan to have a navigation item called "special offers" and link to chronological offers. Now that I am thinking about it, maybe sort the list a la ebay.

Which plugin will work best for allowing members to post their own offers? Should I use classifieds?

Or just set up a custom post type and link to that category?

Thanks
Lori