With Memorial Day weekend “sales” almost here (to be followed by July 4 and Labor Day), remember to take the time to make smart purchases. For 50 years, nonprofit Delaware Valley Consumers’ Checkbook has tracked prices and evaluated retail practices. Our secret shoppers have obtained more than a million prices for everything from alternators to zucchini, from hundreds of retailers and service providers.

All that research adds up to one key piece of advice: If you want a great deal on anything, shop around. Here are 10 sneaky pricing and selling strategies to watch out for while you’re checking off your gift list.

1. Constant Sales

Many retailers constantly advertise big savings. But these promotions usually aren’t discounts at all. After tracking prices of big-ticket items sold at 24 major retailers for 33 weeks, Consumers’ Checkbook found that 21 of the stores claimed to offer discounts more than half the time. For several chains, most of the items we tracked were offered at false discounts almost every week.

These special-but-not-really-special discounts, holiday sales (we’re looking at you, Black Friday), and events are meant to manipulate you into buying items right away. It dissuades you from shopping around. After all, if something is “60% off,” what’s the point of comparing prices elsewhere?

All this good-deal euphoria is also designed to make you snap up more stuff while you’re at it.

2. Inflated Anchor Prices

On the flip side of constant sale pricing is fake “regular” pricing, referred to in the industry as “anchor prices.” Most sellers show prices that are crossed out with lower “sale” prices splashed nearby. Those crossed-out higher “list” prices are rarely if ever charged by the store or its competitors; they’re gimmicks to make that day’s prices seem like bargains.

3. Scarcity Warnings

Demand is high! Supply is low! Act quickly or you won’t get that hotel room/pair of sandals/grill. Usually, it’s a ruse to make you buy now. Don’t let warnings like these deter you from shopping around.

4. Free or Inexpensive Trial Periods

Companies that offer subscriptions often bait their sales hooks with introductory discounts or reduced-cost trial memberships, knowing that once customers sign up, they’ll later pay higher rates month after month.

Every year or two, evaluate your business relationships, particularly your cable and cellphone bills, bank accounts, and credit card accounts to make sure you’re not paying for something you’re not using — or no longer getting the best rate for.

5. Special Treatment

“Because you’ve been a great customer;” “Because we have a crew working nearby;” “Because you’re a parent” or “Over age 65.” Salespeople know if they can convince you that you’re getting special treatment, you’ll feel good about their offers — and might not shop around to find better prices or terms.

6. Fake Deadlines and Limited-Time Offers

Don’t rush. Especially ignore the countdown clocks many companies post on their websites around the holidays. Most of the prices you see will still be there once the “special event” ends.

And don’t assume that “clearance” or “clear out” sales signify amazing deals. You might have seen or heard there’s a best time of the year to buy something because sellers need to clear inventory — for example, wait until the end of summer to buy a new grill. These claims generally have no merit. Checkbook’s shoppers find “clearance” items available for the same price from the same sellers months later.

7. Hidden Fees

Unfortunately, for many services the prices you’re offered are rarely what you’ll pay. Hidden fees cost consumers billions each year. Some of the biggest offenders are hotel- and vacation-booking sites, which often churn out per-night rates in search results that don’t include mandatory “resort” and other fees.

8. Charm Prices

Stores display prices ending in 99, 98, or 95 to make prices appear lower: $9.99 is perceived as “$9 and change,” rather than $10. It’s not the “99” or “95” at the end of the price that affects us. It’s that shoppers pay most attention to the left-most numbers in a price; $199 seems a lot better than $200.

Also effective is pricing using seemingly random amounts — say “$328.46.” This makes it look like prices were carefully set so they are as low as possible.

9. Alternative Payment Methods

Many companies have taken a cue from casinos’ use of chips by pushing alternative payment methods. For example, using Starbucks’ mobile app to pay for daily $5 lattes feels like you’re not spending real money. Gift cards are another way retailers can get you to spend more. They collect money up front for future purchases and tie gift recipients into buying stuff from them rather than the competition. There’s a decent chance the gift card will get lost or forgotten and the company will realize a near-100% profit.

10. Easy Math

Some sellers, especially those with pricey products, advertise discounts as nice round dollar savings (“Save $100”), rather than as a percentage off. The idea is that you’ll more easily absorb the supposed deal. Similarly, some sellers group items for one price (4 for $10). You’ll buy four of them, even if you can buy just one for $2.50. We all fall for this.

Want to learn more? You can view Checkbook’s full list of marketing tactics to be aware of here.

About Consumers’ Checkbook

Consumers’ Checkbook is a nonprofit organization with a mission to educate and help consumers make smarter choices. It offers advice, price comparisons, and in select markets, unbiased ratings of local service providers. It is supported by consumers and takes no money from the companies it evaluates. You can learn more about Checkbook and keep up with its latest reports by visiting Checkbook.org/NFCC.