My Kona Jake has a P2 (700c, non-disc) that I like a lot.
My beater MTB has a no-name steel rigid fork from nycbikes.com- heavy but dirt cheap at $19. Can't remember if they have disc tabbed ones. Also Dimension/Tange have cheap forks, look on any site that has the QBP catalog (aebike, triathlete.com, etc.)