Never pay in advance to a seller that you do not know.
Even if the seller discloses his/her personal information or bank account number, this does not protect you from being cheated.
Always request for the original receipt of purchase from the seller, to verify that he/her is the rightful owner of the item; and to verify that the item is authentic.
Avoid sending goods or payment; instead, meet in person and do COD (Cash on Delivery).
Meet at a public place to deal.
Take extra caution when ...
The offer sounds too good to be true.
The other party keeps pushing you to complete the deal.
The other party claims to be overseas or working offshore.
You are asked for your bank account or credit card number.
You are asked to pay large amounts of money without meeting the seller.
Buying branded items. It is always advisable to meet up with the seller and check the authenticity of the item at a certified shop.