We are hoping to have some basic store functionality in our eBay Live release in June. Of course we also planned on having our inventory feature in November 2005 and you see how well that went. I would anticipate at least some fees with this. We're not going to let people dump a million pieces of lint, fuzz, or trash into our database as there is a pretty big cost associated with even storing an item that will never or rarely sell. At a minimum I'd say something like 1 penny per month per item would be enough to keep the stinky items out.
It does appear we'll have Inventory in our March release though. Oh I suppose I should qualify that as March 2008, lol.