It was the Final Fantasy XIII-2 Lightning in Goddess Armor PAK. It was originally going for around 50 to 60 dollars but the price has increased now. The lowest I've seen was 130 for it.
The seller says it's sealed and he never opened it. Since I knew nothing about PAKs (the only one that I own is the Noctis figure that came with the FFXV UCE) I decided to trust him. Hopefully it pays off haha!
Yeah, that one has increased in price quite a bit. Female PAKs for whatever reason start creep up, but I really didn't think Lightning to increase right now. Then again, it is a cool figure.
Obviously on eBay you want to avoid Asian (China, Taiwan, Hong Kong) sellers mostly. HK can be ok but I'd still be careful. As silly as it sounds, I'd rather pay a UK/US seller the inflated price...but even then it could be lies!
As for selling, maybe mention where you originally purchased? It's something. Of course, if you know the exact things to look for in terms of bootleg vs legitimate then providing that is always good. E.g. a simple box sticker that western suppliers add e.g. Diamond Comics, the legal lines and copyright info etc. Opening a box without completely removing the figure from the blister might be an option, but state it.