5 things to avoid buying during Labor Day sales this year

(CBSNews) -- Labor Day weekend is a popular time for bargain-hunting, but shoppers should be aware that not all products offered will be a good deal. 

Several types are likely to carry lower prices later in the year, especially around Black Friday, said Phillip Dengler of BestBlackFriday.com, a website that tracks sales on Black Friday and other big shopping days. 

Americans are increasingly savvy about sniffing out discounts, yet shoppers can be tempted to make an impulse buy. That's why it's useful to know which types of products are likely to offer good deals -- and which ones don't provide enough bang for the buck. 

Retailers' "sale" prices aren't always discounts, according to new research from Harvard Business School professor Donald Ngwe. Fake sale prices are a common strategy employed by retailers that want to give consumers the feeling that they're scoring a deal. 

In these cases, retailers will post "original" prices and then reflect a sale price on the tag. But the retailers may have never tried to sell the product at the struck-out "original" price. Consumers, however, are willing to pay an extra 77 cents for every $1 increase in the "original" price listed on the item, according to Ngwe's research. 

BestBlackFriday.com said these products are likely to offer good deals during Labor Day sales: 

• Mattresses: Stores are offering up to 50 percent off
• Grills: Look for discounts of about 25 percent
• Summer clothing: Discounts could be as high as 75 percent
• Patio furniture and summer essentials: Lawnmowers may be 25 percent off
• Cars: New 2019 inventory is arriving, so look for deals on 2018 models
• Travel: Sites like Expedia tend to offer deals around Labor Day
• School supplies: Students are back in class, which means stores are cutting costs for pencils, notebooks and other essentials

5 categories to avoid

Fall clothing: Consumers are generally looking for warmer apparel, so retailers aren't cutting prices on sweaters and other fall items. It's best to wait until Black Friday to buy fall clothing, Dengler said.

TVs: Even though Labor Day TV deals "are not horrible," you'll get better prices during Thanksgiving, Black Friday and Cyber Monday, Dengler noted. 

Video games: You can find some discounts over Labor Day, but like with TVs, the big sales will roll around in time for the holiday shopping season. Black Friday deals could include gift cards included with the Nintendo Switch and $50 off the Xbox One X, BestBlackFriday.com predicts.

Toys: While not a big seller around Labor Day, some playthings may be on sale. But retailers tend to cut prices even deeper before the holidays, especially in December, Dengler said. 

Most electronics: Computers will offer a few bargains, such as Dell taking up to 50 percent off laptops and desktop computers, which Dengler said is "a solid deal." Yet it's best to wait until Black Friday and Cyber Monday, when you'll have a bigger selection of products on markdown, BestBlackFriday.com said.