Seven products to never buy in bulk

Is buying in bulk really worth it?

Many consumers assume buying in bulk saves cash. Not always: A recent study in the International Journal of Consumer Studies found that low-income households waste more food than middle-income homes, partly due to bulk buying. Brian Wansink, author of "Slim by Design: Mindless Eating Solutions for Everyday Life," says only half of what families buy in bulk is eaten within a week. The other half goes to waste. "You're so tired of the food you bought, you end up throwing it out," Wansink says. He still believes buying in bulk is cost-effective, but only if you do it right. Here are seven products to never buy in bulk if you're on a budget.

Condiments
Although giant bottles of ketchup and mayonnaise may seem like bargains compared with the price of smaller containers, family finance and frugal living expert Jordan Page advises leaving them on the shelf. "It almost always will go bad before you can go through it," she says. Instead, she suggests waiting until the standard-sized products go on sale, as they do during summer barbecue season.

Over-the-counter medication
"Over-the-counter medications are typically not a good idea in bulk simply because they can expire before you get through them," says Kendal Perez, a spokeswoman for CouponSherpa.com. For example, pills such as ibuprofen or acetaminophen may last a few years, but they can expire much quicker if stored improperly. Perez says it's cheaper to skip the name brands and buy generic products in smaller quantities.

Canned food
Although the shelf life of some canned food can be years, they'll go bad quickly once they're opened. For this reason, Page suggests avoiding bulk cans of pasta sauce or vegetables, despite the seemingly lesser cost per unit. "You would basically be eating spaghetti sauce or crushed tomatoes for two weeks straight if you were trying to use up everything in that can," she says.

Boxes of something you've sampled
It may be tempting to purchase the entire box of a sample you just tasted at Costco, but Perez says it can go to waste quickly if the product turns out to be not as good after the first bite. "You want to make sure you really like it before you have a whole ton of it that you're going to consume," Perez says.

Soda
Buying crates of soda from wholesale stores is a bad idea, Page says. "Soda is one thing that people will tend to buy crates of from Costco or wherever, but you are overpaying," she says. Instead, she suggests waiting until your favorite brand of soda goes on sale, then buying it in smaller quantities.

Sunscreen
Stocking up on sunscreen before hitting the beach? Dr. Melda Isaac, founder of MI-Skin Dermatology Center in the District of Columbia, says you should buy sparingly and be mindful of expiration dates. "If it is left open, then the active chemical ingredients in sunscreens degrade," Isaac says. Instead of using chemical-based sunscreens, she suggests picking up physical-block sunscreens that contain zinc oxide and titanium dioxide as active ingredients, since these have longer shelf lives.

Produce
Although you may find great deals on in-season produce when buying in bulk, fruits and vegetables tend to spoil quicker than shoppers can consume them. "Most of the time, half of the package is going in the garbage," Page says. She suggests purchasing a smaller amount – even if it costs more per pound than buying in bulk – because you'll be more likely to eat it before it goes bad.

More from US News:
12 Ways to Save Money on Food
Your Month-to-Month Guide to Savings
10 Ways Consumers Are Often Duped