andamanen on 29 August 2007
The actual press release doesn't mention anything about price, buying or purchase, but i would guess they would have mentioned it being free in big and bold font if that were the case.
Still, stories from last week with quotes from Sony claim it will be free:
http://www.psu.com/Gran-Turismo-5-Prologue-will-be-free-News--a1105-p0.php
