Coupons can help you save money on stuff you were already planning to buy (even the most casual watchers of Extreme Couponing know this)—but clip carefully, because retailers are smart about using coupons to encourage customers to buy items that are not on their shopping lists. Here are five sneaky ways they work to separate you from your cash.

1. STORES RAISE PRICES BEFORE SENDING OUT THE COUPONS. 

Your favorite online store is having a sale, and it’s ah-mazing. All you need is a handy little coupon code, and you could save half off your purchase. Unfortunately, deals like this are often too good to be true. Kyle James of Rather Be Shopping explains why.

“Be aware of online retailers that are known to raise their prices to full-retail right before releasing a coupon to the public,” James says. “In many cases, the site-wide sale they just had over the weekend will net you larger savings than using a coupon when the prices are at full-retail. Retailers famous for this tactic include JCPenney, American Eagle, Old Navy, Kohl's, and Ann Taylor.” 

To ensure you really are getting a good price, look at the item’s price history using a price comparison site like CamelCamelCamel.

2. THEY HOOK YOU WITH EXPIRING OFFERS.

Act fast! Supplies are limited! Time is running out!

Many coupons, deals, and discounts use this kind of urgent language to trick you into spending impulsively. You feel pressured to buy, and since supplies are limited, you feel like you’re getting something special.

"I always recommend ignoring the signage at retailers and instead look at what the savings percentage actually is, and is the price better than you've ever seen it,” says James. “Signs, and the words on them, are designed to trick our brains into thinking we are scoring a great deal. Often times the ‘limited time’ price is the same price it has been for the past two months.” 

He recommends using a price scanning app like ShopSavvy, which you can use to simply scan the item’s barcode and see the price of that item at nearby stores or online. “By doing so, you let the actual numbers tell you if it really is a good deal and don't rely on the words the store is using to trick your brain,” James says.

3. THEY SET SPENDING THRESHOLDS.

And then there are those coupons that offer awesome discounts—but only if you spend a certain amount. It’s a fairly obvious sales tactic, but retailers still use it for a reason: It works.

"A popular example is 10 percent off $50 or more, or free shipping on $75 or more,” says James. “What this does is create a sense of urgency to spend. Most consumers will look for something to add to their purchase to get to the $50 threshold.”

To combat this, he suggests you only use the coupon on items you were already planning to buy. However, in some cases, it might make sense to spend the extra money to hit the threshold. For example, if your total is $44, and you can save 15 percent if you spend one more dollar, your savings exceed your overspending amount, making the deal worth it. Be careful with this logic, though: It’s easy to use this as a justification to spend more.

“A good workaround is to consider items you actually need, or can gift, and add those to your purchase,” says James.

4. USING COUPONS GIVES YOU A "HIGH."

It sounds hokey, but coupon highs are very real, and there’s research to back it up. A 2012 study found that coupons make us happier and more relaxed. And when we’re happy and relaxed, we might be more apt to spend. Here’s how My Bank Tracker puts it

Happy and relaxed shoppers stay in the store longer and spend more on average than unhappy shoppers. It’s a coupon high and it becomes a buying frenzy. The happier you are and the longer you stay, the more you end up putting in your cart.

5. COUPONS ADVERTISE A PRICIER OPTION.

Coupons are really just advertisements—very effective advertisements. A 2003 study from NYU [PDF] found that grocery shoppers spent more money on an item when that item was accompanied by a coupon. According to the study:

In the coupon-present condition the average price paid by the participants was $2.28, whereas in the coupon-absent condition the price paid by participants was $2.07… This result ... is consistent with our findings in study 1. Consumers are generally price-sensitive and prefer lower-priced products, other things being equal. But when coupons are available for expensive products, their likelihood of purchasing the expensive product increases.

In other words, coupons distract us from potentially cheaper alternatives.