Why Are Coupons Worth 1/100th of a Cent?

The next time a coupon shows up in your mail, take a look at the fine print. There’s a pretty good chance it will read something to the effect of “Cash Value 1/100th of a cent.” Why in the world is that writing on there? And are 10,000 copies of this coupon really worth a whole dollar? Let’s take a look at this coupon quirk.

Putting a Stamp on Customer Loyalty

Before we can answer the coupon-value question, we need to take a peek into a seemingly unrelated footnote in the history of commerce. Let’s talk about the mostly forgotten practice of businesses handing out trading stamps with purchases.

Trading stamps first found their way into merchants’ registers in the 1890s. When customers made a purchase, stores would given them stamps that reflected how much they had spent; a common exchange rate was one stamp for every dime spent on merchandise. Once a customer had saved up enough stamps – often over a thousand – they could swap them for something from the stamp company’s catalog, like a toaster or a clock.

The trading stamps were a runaway success. Supermarkets, gas stations, and department stores would advertise that they gave away a certain brand of stamps to help lure customers in, and the customers could then lick and paste their saved stamps to get “free” merchandise. Everyone was happy, and the system flourished. At one point in the 1960s, S&H Green Stamps printed more stamps each year than the Postal Service did. The circulation of the company’s catalog topped 30 million. The big stamp makers like S&H even built brick-and-mortar “redemption center” stores around the country.

As any economist worth his cost function can tell you, though, the toasters and vacuum cleaners that customers got weren’t free at all. Merchants had to pay for the stamps they gave away, and the cost of the stamp obviously got passed along to the customer in the form of higher prices.

Even in the early days, it didn’t take long for customers to figure out that the system wasn’t quite as rosy as merchants made it out to be. By 1904 New York had enacted laws that forced stamp makers to put a cash face value on each stamp that would enable consumers to bypass catalog redemptions and get money back for their stamps. Other states followed suit.

As one might guess, the individual stamps didn’t get princely face values. A 1904 New York Times piece noted that most stamp makers were given the value of “one mill,” or 1/10th of a cent. That valuation meant that a customer with a full book of 1,000 stamps could redeem it for a dollar. The same piece noted, though, that a customer who used the stamp makers’ catalogs could probably get an item worth three or four dollars for the same number of stamps, so the cash-redemption idea never really took off with most shoppers.

What happened to trading stamps? Their popularity peaked in the 1960s when nearly 80 percent of American households saved stamps, but within a decade the craze had died. Manufacturer coupons that shaved money off of items’ prices became more popular as inducements to get shoppers into stores, and the fuel crisis of the early 1970s sapped away the stamps’ large market at gas stations.

So What Does All This Have to Do With Coupons?

At first glance, coupons and trade stamps wouldn’t seem to have all that much in common. After all, coupons lower the price of an item, while the beef with trade stamps was that they passed a hidden (and often unwanted) cost along to consumers. But some states legally lump trade stamps and coupons in together, so coupons distributed in these states have to bear some printed cash redemption value.

According to the Association of Coupon Professions, only three states require this declaration of redemption value: Indiana, Utah, and Washington. Since many coupons are designed for national distribution, though, the redemption value ends up printed on all of them. As with the old trade stamps, it doesn’t really matter how infinitesimal the stated value is as long as it’s not zero. Thus, you see coupons that are worth 1/10th, 1/20th, or 1/100th of a cent.

So Can I Round Up 20 Coupons and Get a Penny?

In theory, yes. It’s hard to find reliable, concrete examples of someone schlepping in a hundred coupons to swap them out for a penny, but the web is full of anecdotes in which people “test the fine print” by trading in a giant stack of coupons for their face value at the supermarket. In all likelihood, though, you’d need to mail the coupons to the issuing company, which is a pretty lousy financial proposition given the price of stamps.

If you’re sitting on a big pile of Shake N Bake coupons, you might as well give it a try; your supermarket will probably gladly surrender a penny to ensure you don’t make a scene.

Big Questions
Why Do Onions Make You Cry?

The onion has been traced back as far as the Bronze Age and was worshipped by the Ancient Egyptians (and eaten by the Israelites during their bondage in Egypt). Onions were rubbed over the muscles of Roman gladiators, used to pay rent in the Middle Ages, and eventually brought to the Americas, where today we fry, caramelize, pickle, grill, and generally enjoy them.

Many of us burst into tears when we cut into one, too. It's the price we pay for onion-y goodness. Here's a play-by-play breakdown of how we go from grabbing a knife to crying like a baby:

1. When you cut into an onion, its ruptured cells release all sorts of goodies, like allinase enzymes and amino acid sulfoxides. The former breaks the latter down into sulfenic acids.

2. The sulfenic acids, unstable bunch that they are, spontaneously rearrange into thiosulfinates, which produce a pungent odor and at one time got the blame for our tears. The acids are also converted by the LF-synthase enzyme into a gas called syn-propanethial-S-oxide, also known as the lachrymatory factor (or the crying factor).

3. Syn-propanethial-S-oxide moves through the air and reaches our eyes. The first part of the eye it meets, the cornea, is populated by autonomic motor fibers that lead to the lachrymal glands. When syn-propanethial-S-oxide is detected, all the fibers in the cornea start firing and tell the lachrymal glands to wash the irritant away.

4. Our eyes automatically start blinking and producing tears, which flushes the irritant away. Of course, our reaction to burning eyes is often to rub them, which only makes things worse since our hands also have some syn-propanethial-S-oxide on them.

It only takes about 30 seconds to start crying after you make the first cut; that's the time needed for syn-propanethial-S-oxide formation to peak.


The onion's relatives, like green onions, shallots, leeks and garlic, also produce sulfenic acids when cut, but they generally have fewer (or no) LF-synthase enzymes and don't produce syn-propanethial-S-oxide.


Since I usually go through a good deal of onions while cooking at home, I've been road testing some of the different methods the internet suggests for reducing or avoiding the effects of the lachrymatory factor. Here's what I tried:

Method #1: Chill or slightly freeze the onions before cutting, the idea being that this will change the chemical reactions and reduce the gas that is released.
Result: The onion from the fridge has me crying just as quickly as room temperature ones. The one that was in a freezer for 30 minutes leaves me dry-eyed for a bit, but by the time I'm done dicing my eyes start to burn a little.

Method #2: Cut fast! Get the chopping over with before the gas reaches your eyes.
Result: Just hacking away at the onion, I get in the frying pan without so much as a sting in my eyes. The onion looks awful, though. Doing a proper dice, I take a little too long and start tearing up. If you don't mind a mangled onion, this is the way to go.

Method #3: Put a slice of bread in your mouth, and cut the onion with most of the bread sticking out to "catch" the fumes.
Result: It seems the loaf of bread I have has gone stale. I stop the experiment and put bread on my shopping list.

Method #4: Chew gum while chopping. It keeps you breathing through your mouth, which keeps the fumes away from your eyes.
Result: This seems to work pretty well as long as you hold your head in the right position. Leaning toward the cutting board or looking right down at the onion puts your eyes right in the line of fire again.

Method #5: Cut the onions under running water. This prevents the gas from traveling up into the eyes.
Result: An onion in the sink is a hard onion to cut. I think Confucius said that. My leaky Brita filter is spraying me in the face and I'm terrified I'm going to cut myself, but I'm certainly not crying.

Method #6: Wear goggles.
Result: In an effort to maintain my dignity, I try my eyeglasses and sunglasses first. Neither do me any good. The ol' chemistry lab safety glasses make me look silly, but help a little more. I imagine swim goggles would really do the trick, but I don't have any.

Method #7: Change your onion. "Tear free" onions have been developed in the UK via special breeding and in New Zealand via "gene silencing" techniques.
Result: My nearest grocery store, Whole Foods, doesn't sell genetically modified produce or onions from England. Tonight, we eat leeks!

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Big Questions
What is Mercury in Retrograde, and Why Do We Blame Things On It?

Crashed computers, missed flights, tensions in your workplace—a person who subscribes to astrology would tell you to expect all this chaos and more when Mercury starts retrograding for the first time this year on Friday, March 23. But according to an astronomer, this common celestial phenomenon is no reason to stay cooped up at home for weeks at a time.

"We don't know of any physical mechanism that would cause things like power outages or personality changes in people," Dr. Mark Hammergren, an astronomer at Chicago's Adler Planetarium, tells Mental Floss. So if Mercury doesn’t throw business dealings and relationships out of whack when it appears to change direction in the sky, why are so many people convinced that it does?


Mercury retrograde—as it's technically called—was being written about in astrology circles as far back as the mid-18th century. The event was noted in British agricultural almanacs of the time, which farmers would read to sync their planting schedules to the patterns of the stars. During the spiritualism craze of the Victorian era, interest in astrology boomed, with many believing that the stars affected the Earth in a variety of (often inconvenient) ways. Late 19th-century publications like The Astrologer’s Magazine and The Science of the Stars connected Mercury retrograde with heavy rainfall. Characterizations of the happening as an "ill omen" also appeared in a handful of articles during that period, but its association with outright disaster wasn’t as prevalent then as it is today.

While other spiritualist hobbies like séances and crystal gazing gradually faded, astrology grew even more popular. By the 1970s, horoscopes were a newspaper mainstay and Mercury retrograde was a recurring player. Because the Roman god Mercury was said to govern travel, commerce, financial wealth, and communication, in astrological circles, Mercury the planet became linked to those matters as well.

"Don’t start anything when Mercury is retrograde," an April 1979 issue of The Baltimore Sun instructed its readers. "A large communications organization notes that magnetic storms, disrupting messages, are prolonged when Mercury appears to be going backwards. Mercury, of course, is the planet associated with communication." The power attributed to the event has become so overblown that today it's blamed for everything from digestive problems to broken washing machines.


Though hysteria around Mercury retrograde is stronger than ever, there's still zero evidence that it's something we should worry about. Even the flimsiest explanations, like the idea that the gravitational pull from Mercury influences the water in our bodies in the same way that the moon controls the tides, are easily deflated by science. "A car 20 feet away from you will exert a stronger pull of gravity than the planet Mercury does," Dr. Hammergren says.

To understand how little Mercury retrograde impacts life on Earth, it helps to learn the physical process behind the phenomenon. When the planet nearest to the Sun is retrograde, it appears to move "backwards" (east to west rather than west to east) across the sky. This apparent reversal in Mercury's orbit is actually just an illusion to the people viewing it from Earth. Picture Mercury and Earth circling the Sun like cars on a racetrack. A year on Mercury is shorter than a year on Earth (88 Earth days compared to 365), which means Mercury experiences four years in the time it takes us to finish one solar loop.

When the planets are next to one another on the same side of the Sun, Mercury looks like it's moving east to those of us on Earth. But when Mercury overtakes Earth and continues its orbit, its straight trajectory seems to change course. According to Dr. Hammergren, it's just a trick of perspective. "Same thing if you were passing a car on a highway, maybe going a little bit faster than they are," he says. "They're not really going backwards, they just appear to be going backwards relative to your motion."

Embedded from GIFY

Earth's orbit isn't identical to that of any other planet in the solar system, which means that all the planets appear to move backwards at varying points in time. Planets farther from the Sun than Earth have even more noticeable retrograde patterns because they're visible at night. But thanks to astrology, it's Mercury's retrograde motion that incites dread every few months.

Dr. Hammergren blames the superstition attached to Mercury, and astrology as a whole, on confirmation bias: "[Believers] will say, 'Aha! See, there's a shake-up in my workplace because Mercury's retrograde.'" He urges people to review the past year and see if the periods of their lives when Mercury was retrograde were especially catastrophic. They'll likely find that misinterpreted messages and technical problems are fairly common throughout the year. But as Dr. Hammergren says, when things go wrong and Mercury isn't retrograde, "we don't get that hashtag. It's called Monday."

This story originally ran in 2017.


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