Does anyone know how the cost of the Sega CD (and, especially, the Sega CD II) evolved over the course of its life?  I can find launch pricing, but I'm a little uncertain of how its pricing evolved as it matured.

What I'm trying to imagine is what a CD-based Sega Neptune would have cost.  The Sega Neptune is a cancelled Sega console that was a Genesis and 32X in one.  No pricing for it is known, aside from the fact that it was planned to sell for less than $200 USD.
A CD-based version of the Neptune could have been interesting.  I'm curious how close to the Sony Playstation's $299.99 USD price point such a device could have been (or could it even have been below that?).
While the Saturn was undeniably more powerful than the Neptune, some games showed that the 32X might have been able to come close enough for some consumers, especially if it had a price advantage, and especially since it was offering backward compatibility with Sega Genesis games.  It's interesting to imagine an alternate universe where Sega saw the writing on the wall that the Saturn was going to be too expensive, too hard to develop for, and released only the 32X and the Neptune (especially a CD version of the Neptune).  This would have maintained better consumer goodwill, and left them in a stronger position going into the Dreamcast.