I think there would be too much scamming.
Example:
Scammer: Selling 1 ing lantern!
Player: I'll buy, how much?
Scammer: 10b.
Player: Wait, it's lit.
Scammer: Don't worry, you can extinguish it.
Player: Okay. 
(Trades)
We could easily fix that, just make them the same price and add the same amount into the game.
Defeats the complete purpose of the topic.
Not really, it's going around the topic and making it better by eliminating the whole... scamming process.