Question about SNKRS and new drops.

I'm honestly new to the sneaker game. I started getting into sneakers for resale (Flipping pre-owned finds) but I found a few pairs I like and I'm sure I'll end up starting to collect. I notice the air Jordan 9s in chili red are dropping and they look pretty awesome. I'm wondering though how the hell are these selling on eBay and other sites already if they haven't even dropped yet?? Is the a re-release???

Also is there any way to know how limited the drops are on the app??