At six in the morning, many people aren’t thinking about economics when they order their first cup of coffee.

The decision seems much simpler: coffee, then off to work.

But imagine the cup you’re used to buying for 15 riyals now costs 18. Just three riyals more, but enough to raise an economic question that has been around for decades:

What will consumers do when the price goes up?

They might not stop buying coffee. They might not even feel that the increase is significant. But they may buy it fewer days a week, order a smaller size, look for another café, or simply decide that their daily coffee is no longer worth the new price.

And this is exactly where one of economics’ simplest and most widely used ideas begins: the Law of Demand.

Price doesn’t just change what people want—it changes what they decide to do

In the Managerial Economics course (ECO 506) at Al Yamamah University, Dr. @فائق العكايلة Alakayleh presents the law of demand as one of the fundamentals students need to understand how markets work.

The idea seems straightforward: when the price of a good rises, the quantity demanded falls, and vice versa, all else being equal.

But the word “quantity” is the key here.

An economist doesn’t ask: Do you still like coffee?

Instead, they ask:

How many cups will you buy at the new price?

Coffee may remain part of your routine, but a higher price may lead you to rethink that routine.

That’s the difference between liking a good and deciding how much of it you’ll actually buy at a given price.

Consumers rearrange their priorities

Consumers don’t have an unlimited budget.

Every riyal spent on coffee is a riyal that can’t go toward something else.

So when the price changes, consumers reconsider their choices. If a cup of coffee costs 15 riyals, buying one every day may seem like an ordinary decision. At 18 riyals, they may start to wonder: Do I need it every day?

That doesn’t mean everyone will make the same decision.

But in general economic behavior, a price increase leads to a lower quantity demanded under typical circumstances. This is represented by a downward-sloping demand curve. Dr. @فائق العكايلة’s course material explains this concept using a table that links prices to the quantities consumers choose to buy, then turns that relationship into a demand curve.

Put simply, the curve plots what happens across a list of prices:

Higher price, lower quantity.

Lower price, higher quantity.

But be careful: lower sales don’t always mean lower demand

This is where things get more nuanced.

Suppose a café raises the price of a cup of coffee from 15 to 18 riyals, and its sales then decline.

It’s easy to say: demand has fallen.

But economically, it may be more accurate to say that the quantity demanded fell because the price rose.

The difference isn’t just a matter of wording.

When the price of the good itself changes, with all else held constant, we move from one point to another along the same demand curve. The course material illustrates this with an example involving apples: a price drop from 5 riyals to 2.5 riyals led to an increase in the quantity demanded, as the curve moved from one point to another along itself.

But if something else changes—such as consumers’ income or preferences, or the prices of other goods—the demand curve itself may shift.

It’s a small difference in terminology, but a big one in analysis.

The market doesn’t run on price alone

If coffee becomes more expensive, price is an obvious factor. But it isn’t the only thing that determines what happens.

Consumers’ income may change. A substitute may become available. Their preferences may shift. Their expectations about future prices may also change.

That’s why the chapter in which the professor discusses the theory of demand lists a range of factors that influence demand, including the price of the good itself, the prices of other goods, income, wealth, access to credit, tastes and preferences, population size and composition, and expectations.

This brings us to an important principle of economic thinking:

Don’t attribute everything to the factor you can see right in front of you.

If coffee sales fall, perhaps its price has risen. But perhaps something else has changed.

Economics tries to separate these causes from one another.

The café owner sees the question differently

Consumers see the price increase through the lens of their budget.

The café owner sees it from a different angle:

Will raising the price of a cup make up for the drop in the number of cups sold?

A price increase may mean more revenue per cup, but it may also mean fewer cups sold.

This is where understanding demand becomes important for businesses. Pricing isn’t simply a matter of adding a riyal or two to a product’s price; it’s a decision about how consumers will respond.

That’s what makes the law of demand more than a graph in an economics textbook.

It describes how people make decisions when things become more or less expensive.

Three riyals reveal a bigger story

The difference between 15 and 18 riyals may not seem significant in one person’s budget.

But economics isn’t focused on just one person.

If thousands of consumers make similar decisions, the combined effect will show up in café sales and market activity.

That’s how we move from an individual decision made while looking at a price list to an economic trend that can be measured.

The price changes.

The consumer responds.

And the market records the result.

When coffee becomes an economics lesson

Perhaps that’s why some of the most important economic ideas begin with very ordinary things.

A cup of coffee.

A plane ticket.

A car.

An apartment.

They’re all different products, but they can all lead to the same question:

How do people’s behavior change when prices change?

In the case of coffee, the basic answer behind the law of demand is clear: if the price rises, the quantity demanded tends to fall; if the price falls, it tends to rise, all else being equal.

But the value of the idea isn’t in memorizing it.

Its value is in giving us a better way to understand what’s happening around us.

When you see a price change, don’t just ask:

How much does it cost now?

Also ask:

What will people do next?