Why the same generic costs different amounts at different pharmacies

In 2016, researchers at Saint Louis University phoned pharmacies across a two-state region around St. Louis and asked what a cash-paying customer would be charged for a month of three old heart failure generics: digoxin, lisinopril and carvedilol. They collected answers from 175 stores, 153 chain and 22 independent. The quotes for the same three-drug basket ran from $12 to almost $398, with a median of almost $71, according to a summary of the study² published with the paper in JAMA Internal Medicine¹.

FDA rated those tablets as therapeutically equivalent. Every version of a generic sold in the US has to meet the same FDA standards for strength, quality and bioequivalence. What differed was the price each store chose to put on them. The authors found that the retail pharmacy was the main driver of cost, while dose, therapy duration, ownership type and location did not explain the differences.

A decade later, federal data make the gap easier to measure. The government publishes what pharmacies pay for the drug itself, and that number is tiny for most common generics. An insurance copay, a store savings price and a discount card price can all differ for the same bottle.

What the pharmacy actually paid

For pharmacy drug costs, the best public window is the National Average Drug Acquisition Cost, or NADAC. CMS builds it from a voluntary monthly survey of invoices from independent and chain retail pharmacies and updates it weekly³. It covers the ingredient cost only. Discounts or rebates "that are not reflected on the invoice at the drug line item level" are left out, CMS's methodology says⁴, and so are dispensing costs.

Figures are CMS NADAC values⁵ as of Oct. 28, 2026, national averages. A given pharmacy may pay more or less depending on its purchasing contracts.

For many of the most common generics, then, the drug inside the bottle costs the pharmacy less than a dollar a month. A cash price of $15 or $40 for that bottle is mostly something other than the drug.

Why digoxin cost the most in 2016

Digoxin, the St. Louis study found, was consistently the most expensive of the three, even though it is the oldest. GxRadar's NADAC history suggests why. In January 2016, the average pharmacy acquisition cost for a generic digoxin 125 mcg tablet was about 77 cents, against about 2 cents for lisinopril 10 mg and about 4 cents for carvedilol 25 mg. Digoxin had climbed from about 11 cents in November 2013, part of the wave described in the generic price spikes of 2013 to 2015. By October 2026 it was back to about 13 cents.

So acquisition cost does matter. It sets a floor. But for drugs that cost pennies, the floor sits far below most cash prices, and what a store charges above it is a business decision.

The usual and customary price

When an uninsured customer walks in, the number a pharmacy quotes is its usual and customary price, often shortened to U&C. Pharmacies also report U&C on insurance claims, and some payer contracts reference it.

Federal billing rules sit in the background. Under 42 U.S.C. 1320a-7(b)(6)(A)⁶, the government may exclude from federal health programs a provider that bills Medicare or Medicaid substantially more than its usual charges without good cause. Pharmacies commonly pair a posted price with lower prices offered through separate store savings programs or third-party discount cards, each with its own contract terms.

For a shopper, the price depends on how you ask.

Costs that sit outside the bottle

Everything else in the price pays for running a pharmacy: pharmacist and technician wages, rent, software, claims processing, inventory and losses. A store filling a large number of prescriptions a day spreads those fixed costs more thinly than a small one. Our piece on how pharmacies get paid breaks down the dispensing side.

Purchasing differs, too. A store buying through a large group purchasing arrangement may pay less per tablet than a single store buying alone. NADAC averages them together, so a given pharmacy's real cost can sit above or below the benchmark.

How insurance contracts pull in different directions

Most US prescriptions are paid through pharmacy benefit managers (PBMs), which build pharmacy networks and set reimbursement rates for health plans and employers. The market is concentrated. The three largest PBMs processed nearly 80 percent of the roughly 6.6 billion prescriptions dispensed in the US in 2023, and the six largest more than 90 percent, the Federal Trade Commission said in its July 2024 interim staff report¹⁰. The FTC also reported that reimbursement terms in PBM contracts with independent pharmacies often do not clearly show the final payment.

Insurance can produce the odd case where a copay is higher than the cash price, and for years some contracts barred pharmacists from saying so. Congress ended that with two laws signed on Oct. 10, 2018. The Patient Right to Know Drug Prices Act⁷, which began as Senate bill S. 2554⁸, covers group health plans and insurers. The Know the Lowest Price Act of 2018⁹ covers Medicare Part D plans and applies to plan years beginning on or after Jan. 1, 2020. Both stop plans from preventing pharmacists from telling patients that paying cash would cost less. When that comparison makes sense is covered in when the cash price beats the copay.

Asking about price at the counter

A few plain questions tend to surface the lowest number. Ask whether the cash price is lower than your copay; pharmacists are allowed to tell you. Ask whether the store has its own savings program for generics, and whether a 90-day supply changes the per-tablet price. Any change in quantity or product is one to raise with your pharmacist or prescriber, who can confirm it fits your prescription. Our guide to asking for the cash price includes a script.

The St. Louis researchers found that a few pharmacies charged less than $25 for a 30-day supply of all three drugs, the study summary noted². At GxRadar's October 2026 NADAC values, 30 tablets each of digoxin 125 mcg ($3.84), lisinopril 10 mg ($0.54) and carvedilol 25 mg ($0.97) would cost a pharmacy about $5.35 in ingredients.