Consumers have voted Trader Joe's the top U.S. grocery chain in America for the second year in a row, according to Dunnhumby's annual Retailer Preference Index. That's in part because Trader Joe's stresses great customer service. (Did you know that you can ask an associate to try any of the products in-store? You can!)

The chain offers lots of bargains as well as quirky products you don't see anywhere else, which helps it stand out from the crowd.

But it's often those specialty items, as well as certain other staples, that can end up costing you, according to frugal shopping expert Lauren Greutman. "They do such a great job marketing and packaging and making everything look pretty, so we spend a lot of extra money," she says.

Save your cash on these six products that are not worth buying at Trader Joe's.

Meat and seafood

"It's so much more expensive, and honestly, I think the packages don't have a ton in them," Greutman says — especially the chicken.

A 1-lb. package of organic chicken sells for $6.49 at Trader Joe's, according to local prices listed on Basket, a grocery price comparison app. Meanwhile, a comparable package at Walmart sells for $4.94 and at Costco for $4.99.

If you're watching your diet, you may also want to skip the store's marinated meat, including chicken, beef and pork. The CheatSheet found that four ounces of Trader Joe's Korean-inspired boneless beef ribs had 860 mg of sodium, which accounts for 36 percent of your recommended daily intake.

When it comes to meat and seafood, Gruetman prefers to shop at Aldi. "They have a really nice selection of organic meat and products like wild caught salmon and stuff like that," she says. Right now, Aldi has fresh Atlantic salmon on sale for $7.49 per lb. (it's normally around $7.69 per lb., according to Basket), while Trader Joe's is selling comparable fresh salmon for $9.99 per lb.

Aldi U.S. and Trader Joe's are independently operated companies with distinct but once-related corporate parents. It could be said that Aldi and Trader Joe's are "estranged cousins."

Rice

Rice is relatively pricey at Trader Joe's, and frozen rice is particularly expensive. "You're going to pay more money for that convenience," Greutman says. A 3-oz. package of frozen brown rice sells for $2.99, according to Basket. ShopRite has a 12-oz package of frozen, steam-in-a-bag brown rice for $1.79, according to Basket.

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Buying uncooked rice elsewhere would provide even bigger savings. Walmart has 16-oz bag of Great Value brown rice for $0.78, according to Basket.

That said, TJ's frozen grains may save you time, so sometimes it can be worth spending a little more on them. "I still am a sucker for their cauliflower rice," Greutman says, "because cooking with cauliflower is a pain in the butt."

Frozen sides

Trader Joe's is known for their delicious frozen meals and sides, but pay attention to the fine print when you're shopping: You might be paying more for less, Greutman says. To be sure you're getting a good deal, "be careful to look at how much is in the bag."

For example, Greutman says, the grocery chain sells a really good frozen Mandarin chicken meal that's not very expensive: It's priced at around $5. A similar orange chicken frozen dinner offering from Newman's Own sells for $7.79 at Target, according to Basket.

But TJ's sweet potato fries are "a little bit more money than I'm willing to spend for half the amount that I get at the regular grocery store," she says. A 15-oz package of sweet potato fries sells for $2.29 at Trader Joe's, while Walmart sells a 20-oz bag of its Great Value brand for $2.

Vitamins

Bottles of vitamins and supplements can be expensive no matter where you get them. But Greutman recommends avoiding Trader Joe's when you're looking to restock. Otherwise, she says, "you're going to spend a lot more money."

For example, Trader Joe's sells a 100-count bottle of vitamin B tablets for $5.99, while Target sells a comparable bottle of Nature Made vitamin B tablets for $4.67 and Walgreens for $4.75.

Instead, Greutman says, watch for sales at your local grocery store. Or try a health food market in your area, since those will often offer samples or coupons.

Certain cereals and snacks

"One thing I think is really overly expensive is their cereal and snack food," Greutman says.

If you watch sales at other drug stores and markets, you're often able to get various kinds of cereal for less. Basket reports that a 13.5-oz box of TJ's Honey Nut O's is $2.49. At RiteAid, a 17-oz box of Honey Nut Cheerios cereal is on sale for $2.50.

The difference may not always be stark: A basic 15-oz box of Joe's O's is $1.99, according to Basket, whereas Aldi's Simply Nature brand of organic toasted oats cereal is $1.99 for a 16-oz box. Still, it's usually worth your while to shop around.

Snacks such as cookies and granola bars are generally overpriced as well, says Greutman: "All of those are impulse buys and I think specifically packaged to be quick buys, and you spend a lot of money."

Organic milk

Part of the promise of Trader Joe's is the quality. So while the store does sell organic milk, it's often more expensive than what's sold by competitors.

"It's not terribly priced, but you can find it for a lot cheaper other places," Greutman says. For example, a half gallon of Trader Joe's organic, 2 percent milk sells for $3.29, according to Basket. The same size container of Aldi's Simply Nature sells for $2.69 and of Walmart's Great Value organic milk for $3.

Don't miss: 8 foods you should always buy at Trader Joe's

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