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: kids games: 1. First-class driver without a box 300 RSD 2. Roadblock 1000 RSD 3. Hippos 100 RSD 4. Cacophony 300 RSD Center near the Fish Market