If you've used player auction houses in an MMO, chances are you have experienced significant pricing errors from both sides of the equation - as the player who screwed up and listed an item for a fraction of its value, and as the person fortunate enough to grab a major windfall as a result. As interactions between cash shops and tradeable currency/items increase, the stakes feel somewhat higher.
I snagged an item I've been camping on Neverwinter's auction house that typically sells for around $30 worth of Astral Diamonds for a mere $1 worth of AD. This was almost certainly a pricing error on the part of the seller - opening the lock boxes that the item drops from requires a key that costs $1.50 worth of AD so it's pretty unlikely that anyone would sell any of the good prizes for less than the cost of a single key.
I haven't equipped the thing yet. I've done nothing wrong here, and I probably wouldn't think twice about it if it were just in-game gold - as I said, everyone makes these mistakes, you live and you learn. The thing that bugs me is that this currency is so close to effectively real money. It's possible that $20 worth of diamonds really matters to the person who made the error, because they don't have much money to spend on games. Back in the subscription days, everyone could be assumed to have the $15/month price of admission on hand, and capitalizing on someone's mistake for gold was not going to take away something that they paid money for.
Should the mechanics of auction houses be different when there's sort-of money at stake? Or is it best to let people learn from their hard knocks?