I broke mine up into parts and sold on ebay, but you may get more on a forum or as a lot- also the Turbo market is kind of funky- the prices flux a lot.
I got $50 for the dock & A/V cable( I think that's a bit high, but that's where the auction ended), $50 or 60 for the cd player, $5 for the system card and $10 for the briefcase. I sold the TG16 with controller, RF, AC adapter(10.5V) and Keith Courage for $30. So about $140-150 after my fees and such.
Everything was in good shape- not mint, but pretty nice.
If you shop around you can get a Duo-R or RX for about $150-$200 shipped. I got my RX for $250 shipped, but it came with 5 games and the original 6 button controller. It was all close to mint.
Hope that helps-