a place for zinesters - writers and readers
Sweet Candy Distro does zine grab bags...I think that's the closest I've ever seen to a "used" section, although it's a bit more random than what you're talking about I think.
A used section like you describe it would be cool I think. Maybe even people could trade their old zines for some of the newer ones the distro stocks? (Although I have no head for business, so I don't even know if that would be practical for a distro to do...)
I have to agree with Laura-Marie.
I know that Ciara Xyerra found one of her zines marked up to $9 at a used bookstore in Portland. That is just absurd.
With the Richmond Zine Fest we sell donated zines in grab-bags as a fund raiser. We also have some loose zines that we sell at a "name your own price" sort of deal, since they are all for donation.
The other issue with this is that the person whose zine is being sold may not really want that zine to be distroed or sold anymore. Such as a back issue of a really personal zine that they have put out of print for a reason. I can remember an issue with the zine "M is for Monster" (a zine about rape and assault) being sold on eBay when the writer had put it out of print purposefully.