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 great children's books, all in perfect condition. Hoffman - works, the Nutcracker and other magical stories (gift edition). Carroll - Alice in Wonderland, Alice in the Looking Glass (hardcover). Flon - Flon and Musette - a touching illustrated book.