Nvidia's GeForce 9500 GT units based upon a 55nm process won't arrive until 4Q 2008. Other cards are already being manufactured with a 55nm process, but Nvidia is not yet ready to bring the 9500 GT to market with the new process. It's supposed to be a replacement for the low end of the 8000 series cards, particularly the 8600 GT, and will be an "entry-level" offering.
The reduction in process comes with a reduction in price, with a retail price estimated to be as low as $65. AMD's CPU half may still be struggling, but the recent slew of GPUs coming out from them has given Nvidia quite a bit of shock, and may be in part responsible for the low cost of Nvidia's latest offerings.