Even if you’re usually a really smart shopper, it’s easy to go overboard at the outlet mall.

There are so many stores, so many temptations, and everything is a great deal—right?

To find out when it really pays to shop the outlets, ShopSmart, the shopping magazine published by Consumer Reports, had its secret shoppers buy the same items in the designer’s retail store, in a department store and at the outlets. The results: some big variations in price. The outlets often save you lots of money—more than 70 percent in some cases!

But remember that outlets don’t always have the best selection of sizes and colors. If you see an item you love in a boutique or department store, you might be smart to snap it up. And if you have a coupon or tap a great sale, you might be able to get a better deal at a retail store. For instance, ShopSmart found a Juicy Couture shirt on sale at a Juicy Couture store for $89. That’s 29 percent cheaper than the shirt its shoppers bought at the Juicy Couture outlet. And that’s not taking into account the gas and tolls you’ll need to pay for to get to the outlet.

“The trick to outlet shopping is knowing how to spot the best deals— and knowing when to leave something on the rack,” said Lisa Lee Freeman, editor-in-chief of ShopSmart. “So we did the legwork for you, sending out secret shoppers to see how the prices compared.”

Among ShopSmart’s findings:

• Prices are good, materials can vary. The outlet outfits ShopSmart purchased tended to be a lot less expensive— about 60 percent—but the materials and construction were also different, explaining some of the discounted price.

• Shop the outlets from a computer. Lots of retailers have online outlet sites with all kinds of deals, saving you gas and toll money.

• Outlets do carry current seasons at deep discounts. ShopSmart found that plenty of items were available in retail stores and the outlets at the same time, but the items in the outlets can save shoppers lots of money —more than 70 percent in some cases.

Before you go:

1. Have a plan of attack. Check the outlet mall’s Web site for maps, printable coupons and special promotions.

2. Time it right. Outlets have similar schedules to retail stores; extra savings can be found around the holidays, though they will be much more crowded at those times.

3. Get the coupons. Major outlet malls offer coupon books at a cost, so check outlet Web sites, as some will have a voucher to get the book for free if you sign up for their membership club.

4. Log on. Check outlets’ Facebook accounts. Also type in the name of the individual stores and the word “outlet” into a search engine and you may pull up additional savings.

Once you’re there:

1. Spot the good stuff. Some outlets sell garments that were previously at retail stores, while others sell lower-priced clothing made specifically for the outlet. If you are uncertain, ask a salesperson.

2. Don’t go crazy. Just because it’s in an outlet center doesn’t mean deep discounts. The item could be the same price as regular full-price stores, so use your Web-enabled phone to go to a price-comparison site.

3. Chat up the salesperson. You can find out little-known details, like when new shipments will arrive and that prices ending in certain numbers can indicate a clearance or limited quantity item.

4. Join the club. Many outlet stores have frequent-shopper programs that offer additional savings, such as coupons after you spend a set amount or bonus savings on your birthday.

5. Understand the return policy. They are often stricter at outlets than at retail stores of the same name.

By the editors of Consumer Reports at www.consumerreports.org .