These include dairy products, fruits, vegetables, meats, and bread products. You spend more money when you travel up and down the aisles, Pay attention to end of aisle displays. Sometimes they include foods that are truly on sale. Other times, they include foods that the store wants you to purchase, but may not be on sale. You might want to check the unit price of the other brands when you travel down the aisle.
Displays can focus on products that go together.
For example, see if your store has taco chips displayed with salsa or holiday foods grouped together. The foods grouped together may not be on sale at all, while many people have the impression that they are. Do not go food shopping when you are hungry. I have done that in the past and foods that I did not plan to purchase seem to fly into the carriage. Weigh fruits and vegetables priced by the piece, like melon or broccoli.