A gamer friend of mine here in Japan offered to let me take as many of his old PC Engine games as I liked. He had about 30 total, and among them was Sapphire. I told him how much it was really worth, and he decided to keep it to sell later, along with a few other valuable games. I took Cotton, Spriggan, Bomberman 93, Aero Blasters, Street Fighter II, Anearth Fantasy Stories, and two or three more.
I also picked up an unboxed Duo-RX for 7000 yen, or about $70, and another unboxed one in mint condition for 9000 yen, which I was pretty happy about.
Finally, I picked up a new PC-FX that had been opened once but never played (this was apparent by the sealed packaging of everything inside) for about 10,000 yen. Later, I got a quite used one for $30, which I sent to a friend as a gift.