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.
Selling a Fender Squier Stratocaster electric guitar in excellent condition, complete with a compact Vox headphone amplifier, Yamaha headphones, a good guitar case, a capo, an Aux cable with two mini-jack -> jack adapters, and a pair of picks. The amplifier has three gain modes, several echo modes, three adjustments (gain, tone, volume), an input jack, an...
