I've been in the market for, and have bought some, Contax stuff lately, and I find that Buy It Now prices are way, way higher than the ending prices of regular auctions. I've gotten really good stuff here on this board and on eBay for cheap. If you go CZJ you can get especially good deals on lenses. I paid $75 for a CZJ Sonnar 1.5 though admittedly it needs collimation, which will add some money. But you could find a good CZJ Sonnar 1.5 for $100-150, I bet.