I like to buy produce when it is in season. You get the best price that way. Properly handled several fruits and vegetables can be frozen for later use. Corn on the cob is very abundant during the hotter summer months. Leave the shuck on and it freezes well for winter use. Frozen berries are simple to cook with. Buy blueberries during the early summer months and freeze them. On a cold winter morning you can use them to bake up a batch of warm blueberry muffins. Most berries will freeze well, but a few will turn too mushy for use. You can typically find fresh pineapple on sale during the fall holiday season. Slice the pineapple and freeze it using wax paper to keep them from sticking together. You've got perfect layers for a pineapple upside cake, a tempting treat in the course of hotter summer gatherings. Check with your produce department if you have any questions on the advantages of freezing produce.
If you do not plan on a long term use for your purchase try a few sensible approaches to prolonging its use. Be mindful of the most advantageous means to store your produce. Potatoes, onions, and garlic should not be stored in the refrigerator. The temperature required to maintain a fridge is too low for these items to remain healthy. The moisture promotes mold growth and breaks down the starches that not only add flavor, but ward off deterioration. One note though, if you prefer to use your potato or garlic to reproduce leaving it in a cold moist place will activate the reproduction process allowing you to transfer the seedling to your spring garden.
Some vegetables are best stored wrapped in a paper towel and stocked in a loose plastic bag. Lettuce will last longer if you thoroughly wash it before it is stored. Make sure it has dried completely before you bin it. Wrap in a dry paper towel and place in a plastic storage bag (preferably a grocery bag) and keep it in the refrigerator. Avoid putting corn and lettuce in a crisper bin unless they are by themselves. They tend to bruise easily which promotes spoilage.
Again we'll go back to my all time favorite house hold products. Soak fruit in a mixture of cold water and baking soda. Use no more than 3 tablespoons per 3 quarts of water. The acid in baking soda perks up your purchase. Rinse thoroughly after 30 minutes and return to refrigerator once dried. Sprinkle baking soda on the bottom of your crisper to absorb excess moisture. Moisture invites mold growth so it's beneficial to keep it under control.
Spray the goods with vinegar. Cider vinegar or white distilled vinegar will both work. The acid in vinegar breaks down the excess chemicals that manufactures add for shipping. These chemicals may allow the product to look healthy and shiny on the shelf, but it also breaks down natural preservatives. You can substitute pure lemon juice for the same purpose. As a final step you may want to spry with a mist of hydrogen peroxide. This will sanitize the surface of the produce and remove any deterioration that may already be sneaking in. Be sure to rinse and dry before you stock your bargain.
To give you investment the longest shelf life I prefer to can produce that is applicable. See my article "Canning" on this same blog. It's a lot easier than you think, and cheaper than purchasing canned goods from a grocery store.