in Northern California, at Safeway Stores. I found KAF AP, Bread, Whole Wheat and White Whole Wheat all on sale today (and until April 6th accoring to the shelf tag) for $3.99 / 5# bag. That is not as low as I saw it there at Christmas, but it is quite a lot better than the $5.99 usual everyday price en my small town.
I also found KAF AP flour at Smart and Final today for $8.19 per 10# bag. That is not quite a low as Safeway, but still better than the everyday price at Safeway. It was not marked as a sale or promotional item, but I imagine it is, nonetheless.