Summarize this article in one sentence.
Most grocery stores post the price per ounce (or kilogram) along with the total cost of a product. Compare the prices per ounce between 2 or 3 different brands to find which one offers a better deal. For example, say that 1 brand of peanut butter offers 20 oz for 8¢ an ounce, while another company offers 30 oz for 5¢ per ounce. While you’ll be buying a larger amount of peanut butter, the second company offers a much better deal.  If the price per ounce isn’t listed, a pocket calculator can be handy. Just divide the total price by the number of ounces. Consider buying private-label or store brands. In many cases, these rival the quality of the better-known brands at a significantly lower cost. When your grocery store offers a great discount on an item that you like, take advantage of the sale and stock up! The item probably won’t be on sale for very long, so you can save money by buying, say, 6 months’ worth of ground beef at once. This is especially helpful for nonperishable items or for foods that can be frozen, including meats and veggies. Keep the stockpiled foods in the freezer until you need them to prevent them from spoiling. Stocking up on a food that you won’t use defeats the purpose of this step. If you rarely eat artichokes but they’re on sale 10 for $1, it’s probably smart not to take advantage of that particular sale. For example, visit your grocery store early and shop for baked goods early in the day. That is when bakeries and grocery stores mark down their day-old items. Also try to shop for meat later in the day. That is when the meat department marks down items about to go past the “sell by” date. This meat is perfectly safe and can be frozen for later use. Your grocery store may have other recurring mark-downs that you can capitalize on. For example, some grocery stores slash their prices on Sunday evenings to prepare for new incoming inventory on Monday. Processed items may be convenient—and make up a large part of many people’s diets—but they’re usually more expensive and less nutritious. Instead of processed foods, look for whole grains and fresh produce that have more nutritional value. Also try cutting back on expensive meat and dairy products. Look for ways to get your protein from items like beans and nuts.  For example, buy inexpensive but healthy foods that are easy to fix, such as oatmeal and legumes. Shop on the periphery of the store where fresh produce is located. Avoid the center aisles where processed and packaged food is found. Wholesale clubs usually sell in bulk at cheaper prices than their competitors. They’re especially good for finding cheap packaged foods, and often also have affordable delis and bakeries. Try shopping for your processed and pre-packaged foods at a wholesale club. Also buy durable goods that you’ll need in the future, such as bath tissues, grains, canned food and dried beans. Common wholesale clubs include BJ’s, Costco and Sam’s Club.  These stores do charge an annual membership fee, but that’s easily offset if you shop there even 1–2 times a month. If you buy mostly fresh produce and not much packaged food, wholesale clubs are probably not for you.

Summary:
Compare prices between similar items to find the cheaper. Stock up on discounted foods that you know you’ll use. Shop early and late in the day for specific discounts. Avoid buying unnecessary processed foods, meat, and dairy. Join a wholesale club to buy bulk food at discounted prices.