5 items to buy in bulk (and 4 that aren’t worth it)

Buying ingredients in bulk and opting for the dual-package of peanut butter at Costco instead of the puny jar from the grocery store can save you money, but it may end up costing you more.

The trick is always to price shop (calculate the per-ounce price at each store to see which is in fact cheaper)—and be sure you can finish what you bought before the expiration date. Leaving a store with 96 ounces of peanut butter is a win in our book, but since the average shelf life of PB in an open jar is two to three months, you’d be dumping hard-earned cash down the drain if you have to toss it.

To help you avoid the guilt of wasting food and money (plus a huge stomachache eating all that peanut butter yourself), we consulted a money-saving wizard who shares her tried-and-true secrets of bulk buying.

Buy This in Bulk:

Annette Economides, along with her husband, Steve, and five children, are known as America’s MoneySmart Family. Leading an extremely frugal (and fulfilling) life, they’ve managed to accomplish impressive goals, such as paying off their first home in nine years on an annual income of approximately $35,000. Here are some of the ways she uses bulk buying (and buying in smaller amounts) to shave hundreds of dollars off her monthly grocery bill.

What You Should Buy in Smaller Quantities:

Happy deal hunting!