If your local grocer is like ours, it has a small kosher section; although the items tend to be of higher quality, the prices are correspondingly higher and therefore I rarely shop the kosher section.
However, this time of year is the exception. In anticipation of Passover, the store fills its Seasonal section with "Kosher for Passover". It's got plenty of chocolate, large containers of matzos, and many other foods that would fit right into a non-kosher diet, e.g. cans of soups and bottles of juice. They tend to be of a brand we never see except this time of year, and they're a little pricey due to their special status.
But AFTER Passover, the store marks these items down substantially. Who wants to warehouse food to sell next year? These markdowns can make it very much worth stocking up. While post-Passover sales are far from the only post-holiday sales, unlike those after Halloween or Easter, the foodstuffs go far beyond candy and fruitcake. For example, today I just bought cans of kosher tomato sauce at half the price of non-kosher. (Although let's not overlook the chocolates ...)
These bargains don't last long; the whole point is to move the product off the shelf and if you wait, you'll have to wait until next year. A side benefit of shopping post-Passover sales is the chance to broaden your appetite a little (who knows, you may discover some food that's new to you that you like), but the real point of this tip is saving money by shopping post-Passover food clearance. And who doesn't like to save money?