Thanks DAZDA for the reply. Supply and demand is indeed a major paradigm for the price of cars and 2 seater s30's in good condition are hard to come by these days. The shifting patterns of buyers tastes and the value for money equation also have some implications. I've been looking for a nice 260z coupe for a while in sydney as an automatic for for a cruiser but once the price crosses that 15k price I get a little nervous, as I feel it would want to be a really good one. It also brings other cars into the equation when you get to this price level. Some people then make the decision that if they can't afford a coupe, maybe they should opt for a 2+2, 280zx, z31, z32, which is more affordable and perhaps in better driving condition. In concord there is an orange 240z that has been for sale for 36k and it has been on the market for at least 3 years now. I wonder what price ceiling a 280zx will reach, or will a z31 88 model experience a resurgence. Z32's are currently very cheap, but hard to find a good one. Also if you do find a good one, and you put a lot of K's on it, you may then lose your money.
Emotion also plays a role, which can at times be at odds with rational thinking. For example, I really love the 260z coupes and lets say I can get one for 15k. As I look at one my neighbour tells me for that price I can get a 2001 supra, a 99 GTO, or 97 RX7 or 944s, he can't see the value in my choice. My sister thinks I'm mad because I should go to an auction and get a govt 09 Commodore with 40k's for 15. My mother thinks if I spend a bit more I can get a new car.