Price Discrimination Explained: The Three Degrees, With Examples

Price discrimination is the practice of charging different buyers different prices for the same good for reasons unrelated to differences in cost. When an airline sells the identical economy seat for 180 dollars to one passenger and 520 dollars to another, or a cinema charges students less than working adults for the same film, that price gap is not about the cost of serving each customer. It is a firm with market power capturing more of the value buyers place on the product. Economists sort it into first, second, and third degree, and each one has a distinct method, a set of real-world examples, and a different effect on efficiency and consumer welfare. This guide walks through the three conditions that make price discrimination possible, the three degrees with concrete examples, a worked third-degree calculation, and the welfare verdict AP exams ask you to reach.

Price discrimination is a property of firms with market power, so it lives inside the monopoly model, and you can see the underlying single-price graph it starts from in the monopoly sandbox.

The three conditions required

A firm cannot price discriminate at will. Three conditions must all hold, and if any one fails the strategy collapses back to a single price.

• Market power. The firm must be a price maker, not a price taker. A perfectly competitive firm faces a single market price and has no room to charge more to anyone, so price discrimination is impossible under perfect competition. It requires a monopoly, oligopoly, or monopolistically competitive firm.
• The ability to segment buyers by willingness to pay. The firm needs some observable signal that separates high-value buyers from low-value ones: a student ID, the timing of a booking, the quantity purchased, or a coupon that only price-sensitive shoppers bother to clip.
• The prevention of resale (no arbitrage). Low-price buyers must not be able to resell to high-price buyers. If a student could buy a cheap ticket and resell it to an adult at a markup, the two prices would converge. This is why price discrimination is common in services (a haircut, a flight, a doctor's visit cannot be resold) and rare in easily traded physical goods.

Keep these three in mind, because every real example below is really just a clever way of satisfying the second and third conditions.

First-degree price discrimination

First-degree (or perfect) price discrimination is the extreme case: the firm charges each buyer exactly their maximum willingness to pay for each unit. No consumer surplus is left on the table; every dollar of value becomes revenue.

Pure first-degree pricing is rare because it requires knowing each buyer's private valuation, but several real practices approximate it. Haggling at a car dealership, where the salesperson probes how much you will pay, is an attempt at it. So is a one-on-one negotiation for a custom service, an auction that pushes the price toward the top bidder's valuation, and increasingly, algorithmic personalized pricing that uses browsing and purchase data to tailor an offer to each shopper.

The result carries a striking twist worth memorizing. When a monopolist charges each buyer their exact willingness to pay, the demand curve itself becomes the marginal revenue curve (D = MR), because selling one more unit no longer forces a price cut on the earlier units. The firm keeps selling until price equals marginal cost (P = MC), which is the same quantity a competitive market would produce. So perfect price discrimination is allocatively efficient and eliminates deadweight loss. The catch is entirely about distribution: consumer surplus falls to zero and the entire surplus becomes producer profit. Efficient, but the firm keeps everything.

Second-degree price discrimination

Second-degree price discrimination charges different prices based on the quantity or version purchased, not on the identity of the buyer. Everyone faces the same menu, and buyers sort themselves by how much they buy or which tier they choose. The firm never needs to know who you are; it only needs you to reveal your type through your choice.

Common examples:

• Bulk and block pricing. A wholesale club charging less per unit for larger packs, or a utility that prices the first block of kilowatt-hours at one rate and later blocks at another.
• Versioning. A software product sold in a free, standard, and premium tier, or an airline offering economy, premium economy, and business on the same flight. The seats fly the same route, but the fences (legroom, refunds, boarding order) sort high-value from low-value flyers.
• Quantity discounts and multi-part tariffs. Phone plans with tiered data buckets, or a gym charging a membership fee plus a per-class rate.

The defining feature is self-selection: the seller posts a schedule and lets buyers choose the point on it that fits them. A high-value buyer voluntarily picks the premium version; a price-sensitive buyer picks the basic one.

Third-degree price discrimination

Third-degree price discrimination is the most common form on the AP exam and in daily life: the firm splits buyers into identifiable groups with different price elasticities of demand and charges each group a different price. The group with more elastic (more price-sensitive) demand pays the lower price; the group with less elastic demand pays more.

Examples are everywhere:

• Student and senior discounts. Students and retirees tend to have more elastic demand and more flexible time, so cinemas, museums, and software firms charge them less.
• Peak and off-peak pricing. Trains, movie theaters, and electricity utilities charge more at peak times when demand is least elastic.
• Geographic pricing. The same textbook or streaming subscription sold at different prices across countries.
• Coupons. A coupon is a self-administered segmentation device: only the price-sensitive shoppers spend the time to clip and redeem, so they get the lower effective price.

The firm sets MR = MC separately in each market, which means each group pays a price tied to its own elasticity. This is the inverse-elasticity logic: less elastic demand supports a higher markup.

A worked third-degree example

Suppose an airline serves one route with two identifiable groups. Business travelers have relatively inelastic demand, described by P = 100 - Q. Leisure travelers have more elastic demand, described by P = 60 - Q. Marginal cost is a constant 20 per seat, and the airline can separate the groups (for instance, a Saturday-night-stay requirement that only leisure flyers accept).

For each market, revenue is P times Q, so marginal revenue has the same intercept and twice the slope of demand, and the firm sets MR = MC.

• Business market: MR = 100 - 2Q. Set 100 - 2Q = 20, so Q = 40 and the price is P = 100 - 40 = 60.
• Leisure market: MR = 60 - 2Q. Set 60 - 2Q = 20, so Q = 20 and the price is P = 60 - 20 = 40.

Business travelers pay 60 and leisure travelers pay 40 for the same seat. The higher price lands on the group with less elastic demand, exactly as the theory predicts. If the airline were forced to charge a single price across both groups, it would earn less than the 3,200 in combined revenue this split generates, which is why the separation is profitable and why airlines invest so heavily in fences that keep the two groups from mixing.

Welfare effects: is price discrimination good or bad?

The efficiency verdict depends on the degree, and this is where AP free-response points are won.

First-degree is the clean case. Because the firm produces all the way to P = MC, output equals the competitive level and deadweight loss is zero. Total surplus is as large as possible. Every bit of it, though, goes to the producer, so consumer surplus is wiped out. Efficient in size, lopsided in distribution.

Third-degree is genuinely ambiguous. Compared with a single-price monopoly, splitting the market often raises total output, because the firm now serves price-sensitive customers it would otherwise have priced out, and more output means less deadweight loss. But it does not always raise output, and it clearly redistributes surplus toward the firm and away from the high-value group. The standard AP takeaway is that price discrimination is a tool for a firm to capture consumer surplus as profit, that it can increase efficiency by expanding output beyond the single-price quantity, and that the most efficient version (first degree) is also the most extractive for consumers. You can quantify the surplus areas involved against the single-price baseline with the deadweight-loss calculator.

Keep going

Price discrimination only makes sense once the single-price monopoly graph is second nature, since every degree is a departure from that baseline. Rebuild the profit-maximizing monopoly diagram in the monopoly sandbox, read the full market-power picture, barriers to entry, deadweight loss, and regulation, in the monopoly lesson and the deeper monopoly guide, and lock the definitions of price discrimination and related terms in the glossary. Then rehearse the graphs graders actually score in the draw-the-graph FRQ mode.