Possible soultion for market scams

[magicvader]

Ive had this idea in my head for a while since i have been seeing scamming in the market place
well heres my idea:
There could be some kind of sign when you say buy item # that says what your buying how much its put up for and it also asks you a secondary check to see if you want to buy it so some one dosent like put a apple up for 500 and goes under the item and holds up a rare hat and if you fall for buying it you can cancel the your buying if you see that its a apple on the sign

it would be a great way to stop that scamming
possibly tell me what you think