Reading some comments online, seems Rosewood and Ebony are for $100+, but the Teaks can only be purchased with the headphones. I would like confirmation on this though. Would be a bummer to go for Rosewood, only to not be able to buy the Teaks separately.
EDIT: Corrected price. Teaks are in fact not separate. (Chan states this further down)
Teaks are exclusive for MD, but if you get Teaks, you can still order other wood cups. If I remember correctly I did pay less then $100 for my Rosewood cups. I think it was around $60 or 80$, do not know for sure anymore.