It might work for a system of selling rare items, but it'd be a bit slow for selling your more day to day items.

For more common items I'd rather see a few NPC merchants. Rather than the multiple ward we have now, have a single instance of it with an NPC merchant in each of the stalls.

Each merchant buy and sells a particular type of good respective of the wards we have currently.

Have each item for sale shown with the current lowest price someone has been willing to sell it for along with other items listed as out of stock.