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: BEKANT table, IKEA, 160*80. Large and comfortable, height adjustable. Price 100€. Office chair. Purchased in February, good condition. Bought on Ananas (now it's about 12000RSD there). I'll give it away for 50€. Pick-up, Zheleznichki district
For sale: TP-Link Wi-Fi signal extenders. Features: up to 1200 Mbps speed, dual-band Wi-Fi, access point support, WPS, signal indicators. Price: 5000 dinars each (negotiable).