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.
Scarlett SC-HB42F86 blender. Used for less than a year. Power: 1700 W (you can't find this in Belgrade!) 20 speed modes + TURBO mode. Mini-chopper capacity: 0.6 l. Included: whisk, chopper, measuring cup. Price: 5000 RSD (can be RUB at the Google rate)
