Never pay down a deposit in a bank account until you have met the seller, seen signed a purchase agreement.
No serious private advertisers ask for a down payment before you meet.
Receiving an email with an in-scanned ID does not mean that you have identified the sender. You do this on the spot, when you sign a purchase agreement.
For sale: new dining table, extendable. Dimensions: w90, d190/235/280, h77 cm. Price: 20000 din. Also for sale: new chairs (4 pcs) at a price of 2500 din per piece. Can be sold separately. Pick up at Branka Bajića, Novi Sad.
