In the last NVIDIA press release , there was an information about the price of next generation GPU .
Let us note that GT200 according to NVIDIA estimation will be twice faster than current generation video card , It will include a 512 bit memory system bus , Gddr3 memory and more stream processor (almost doubled in comparison with G92) .
Here is the picture from NVIDIA slide :

Well, 649 $ from the Geforce 280 GTX (1024 MB , GDDR3) and 449$ for The Geforce 260 GTX (896MB GDDR3) .
Currently, the cheapest Geforce 9800 GTX can be purchased for about 300$ while the 9800 GX2 cost about 500 $ (in the best case 450 $ after rebate) , NVIDIA will launch the GT200 video card based on previous generation card price .Theorically the Current card will fall to 300-350 (GX2) and 200-250 (GTX) , This will be a nice update for the hot summer .