I looked around and really couldn't find any selling on any of the major selling places. I've also seen on here people saying between $200 and $150-ish, but even then most of those comments/threads were 6 months old or more. It's hard to say... Obviously $200 sounds great to me, but if that's not what I can realistically get then I'm open to offers.
It's absolutely mint. I bought it about 10 years ago brand new, and opened it about a year later. It stayed inside the system for a few years, got used periodically, and then I moved and it got packed away, then I moved 3 more times and I just never found it again until recently. I already sold off all my other TG/PCE/PCFX stuff months ago, otherwise I'd sell it along with my complete TG-CD attachment I used to have.
Here's a picture of it, I can do more if needed: