a/d/s Atelier System Valuation

I have a four piece system that I haven't used in many years. How can I go about finding out what the market for this system would be?

They are the CC4 control center, PA4 power amp, C4 cassette player, and CD4 cd player.

I would think about $200 to $250 a piece, with the cassette and cd at the low end, the preamp and amp at the higher end. I sold my cassette player, with the dual speed feature for $200 a couple of years ago.