Seems like an old thread but its in one of my specialties so I have to comment
After Auctiva started charging i went ahead and tried ALL of the major alternatives.
the top two contenders were
Ecommerce Solution: Create a Free Online Store and Sell on eBay, Amazon & More and sellers sourcebook, I was eventually taken over by vendio because it had such an easier interface than auctiva, and I didnt know what I was missing with inventory management until i got to use their system.
Back then, they offered a free year of their service to all auctiva members, not sure if that offer still stands, but they do give away a free web store for auctions as a free member.