FDNY Bunker coats are a little harder to come by these days. Due to security that don't let them get into the public like in the past.
Also it's all issued to the member and the property of the city, so you have to give it back to them when you retire.
You can try Ebay but FDNY watches for stolen coats being sold so they try to stop most auctions of FDNY gear. Even more so after a few people dressed up in gear purchased of EBay.