In my part of the country we have a few discount grocery stores [View all]
Near me there is both an Aldi and a Save-a-lot. In season fresh berries are a treat but Aldi usually has very good frozen berries that are reasonable. Save-a-lot has good mayonnaise for about $2/quart here.
Blending mayo and horseradish for is cheaper than buying the prepared sauce and mayo blended with chopped pickles or relish is usually cheaper than tartar sauce.
I read an investment guide by Andrew Tobias a long time ago that said a penny saved is two pennies earned by the time you pay the taxes on it. What I get is that my attention belongs spending and finding a way to do it cheaper will net me more than working longer hours to try making more only to lose some to taxes and such.
When you see canned tuna for cheap, stock up. If you like tuna. 
Memorize or keep a list of the best regular prices of your most often eaten groceries so you will know when a SALE is really a good deal.
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