Hi all! I'm a newbie here and wanted to get your thoughts on a purchase! A little late into the game but I've been looking for the 17S so black caviar boy for a few months now with no luck

There are several resellers on eBay who sell it new for $500-600 higher than what I would have to pay in retail (USD $5,600-$5,700 for the old medium). Do you think the price is worth for the so black caviar and will it come out again in the future? It will be my first Chanel purchase and I'm also worried on the authenticity on eBay but I've done some research and looks like at least 2 are legit

Would love to hear your thoughts thanks!!