Originally posted by: teddyv
There are really two ways the scam works. The first is the simpler, they send you a forged/counterfeit check/money order and you send the item. You find out a few weeks later the check/money order is bogus and by then the buyer is long gone (and your laptop is most likely being used in a Nigerian Internet Cafe to scam even more people.) The second is a bit more devious. The buyer tells you he has a money order/certified/cashiers check already filled out and it is for more than the item you're selling. He will send you the check, and you should Western Union wire him back the excess followed by the item you are selling. You get the check, wire him back the extra, then find out two weeks later the check is bad and you are out the "extra" you sent. A derivation of this is the shipping scam - similiar as above but the buyer wants you to handle the shipping for him. You guessed it, he adds the shipping to the check and you are to wire it to the "shipping agent". The check comes back bad and you are out the "shipping expense", really just another way to get you to send cash to him.
They are getting better and better at it too.