Written and sourced by Vincent Wesley Couey, RxGrab founder. Updated .
Neither wins everything. On the 11 of 17 common generics that both price, Walmart's published list is lower on 5 and Costco on 6, but Walmart's wins are bigger. Basis for every price: 30 tablets (60 for metformin, which Walmart lists by 60), read October 26, 2026.
Read on October 26, 2026. Costco's Member Value Pricing lookup (rx.costco.com), read signed out with Generic selected and the form, strength and quantity filters confirmed on every row, and Walmart's Prescription Program PDF (effective 03/24/2025), each read that day. This is not a hands-on test: we did not fill a prescription at either pharmacy. Prices are published list or lookup prices before tax; what you pay can differ by store, state and plan. This page is not medical advice.
The earlier version said "Costco was lower on all 7 drugs that are on Walmart's list" using an April 2026 Costco snapshot of $1.62 to $5.11, claimed a Costco markup "of roughly 14-15% above wholesale", that Costco must serve non-members "by federal law", brand-name prices for Eliquis, Jardiance, Synthroid and Crestor, Walmart prices for duloxetine and rosuvastatin, and hours, wait times and store counts. Costco's own lookup now shows $6.99 to $10.99 for the same kind of fill, Costco is above Walmart's $4 tier on all 3 and above its $9 tier on 2 of 8, and we could not trace the rest to a primary page. We replaced the table and removed the unsourced claims. The two Costco atorvastatin prices that disagreed ($2.81 and $6.92) are gone: Costco's lookup shows $7.99 for 30 tablets.
Amber to the right: Costco costs more. Purple to the left: Costco costs less. 30 tablets (metformin 60).
Basis: 30 tablets (metformin 1000 mg: 60). A 30-tablet fill is a month only for a once-a-day dose, so use your own tablet count. Walmart "-" means the drug is not on Walmart's published list, so its regular price is not published; the difference is then blank.
Swipe the table sideways to see all columns. The drug name stays in view.
| Prescription | Costco, member pricing | Walmart list | Costco minus Walmart | Lower |
|---|---|---|---|---|
| Atorvastatin 20 mg | $7.99 | - | n/a | only Costco priced |
| Lisinopril 20 mg | $9.79 | $9.00 | +$0.79 | Walmart |
| Amlodipine 10 mg | $8.79 | $9.00 | -$0.21 | Costco |
| Omeprazole 20 mg capsule | $9.99 | - | n/a | only Costco priced |
| Losartan 50 mg | $8.99 | $9.00 | -$0.01 | Costco |
| Sertraline 100 mg | $8.79 | $9.00 | -$0.21 | Costco |
| Escitalopram 10 mg | $8.99 | - | n/a | only Costco priced |
| Furosemide 40 mg | $9.99 | $4.00 | +$5.99 | Walmart |
| Levothyroxine 50 mcg | $9.99 | $4.00 | +$5.99 | Walmart |
| Hydrochlorothiazide 25 mg | $7.99 | $4.00 | +$3.99 | Walmart |
| Fluoxetine 20 mg capsule | $8.99 | $9.00 | -$0.01 | Costco |
| Citalopram 20 mg | $9.79 | $9.00 | +$0.79 | Walmart |
| Trazodone 50 mg | $8.99 | $9.00 | -$0.01 | Costco |
| Montelukast 10 mg | $9.99 | - | n/a | only Costco priced |
| Pantoprazole 40 mg | $10.99 | - | n/a | only Costco priced |
| Meloxicam 15 mg | $6.99 | - | n/a | only Costco priced |
| Metformin 1000 mg (60 tablets) | $7.99 | $9.00 | -$1.01 | Costco |
Sources, all read October 26, 2026: Costco Member Value Pricing (generic selected; "show your Costco membership card at the participating pharmacy"; "NOT insurance"); Walmart Prescription Program list (effective 03/24/2025; the walmart.com list page may carry a newer revision). Cost Plus Drugs prices for the same 17 are on cheapest pharmacy for prescriptions.
Walmart's Prescription Program PDF prices covered generics for up to a 30-day supply at $4, $9 or $15 tiers (with 90-day prices of $10, $24 and $38) plus an albuterol HFA inhaler at $24. Prices may be higher or vary in some states including California and Minnesota; the program is not available in North Dakota; prepackaged drugs are covered only in listed unit sizes; and pricing may be limited to select manufacturers while in stock. Walmart also says you may pay more or less than the program price depending on your health plan, and that prescriber permission may be needed to change a 30-day prescription to a 90-day one. Walmart Mail Service has its own $10 and $24 prices for 90-day supplies of certain listed drugs. Sam's Club is not part of the program: the terms name Walmart and Neighborhood Market pharmacies and Walmart Mail Service.
Costco's Member Value Pricing is a price lookup at costco.com/cmpp (rx.costco.com). Costco says its member prescription program is "NOT insurance", is a prescription drug discount card program for eligible Costco members and their eligible dependents, that any Costco member can join, and that you show your membership card at the participating pharmacy to receive the discount, which is determined at the time of purchase. Two traps from reading it: the lookup can default to the brand (amlodipine defaulted to Norvasc at $1,119.71 for 90 tablets, levothyroxine to Synthroid), and the descriptive subtitle can lag the quantity filter. Select Generic and check the filters.
DRUG AND STRENGTH: ______________________ TABLETS ON MY PRESCRIPTION: ______ FOR ______ DAYS 1. What is your cash price for this generic, strength and tablet count today? 2. Costco: is that the member price in your online lookup, and do I need my membership card? Walmart: is it the $4, $9 or $15 program price? 3. Costco says I can buy prescriptions without being a member. What do I pay without a card, and what does membership cost? 4. Do you take my insurance? What is my copay, and which is lower, the copay or the cash price? 5. What would 90 days cost, and does my prescriber need to write a new prescription? 6. Is this the price at this exact store (and state)?
On furosemide, levothyroxine and hydrochlorothiazide Walmart is $3.99 to $5.99 below Costco.
Pick: Walmart for these 3.
Costco is $0.01 to $1.01 lower on 6 of the 8; Walmart is $0.79 lower on lisinopril and citalopram. Use whichever is nearer, and Costco only if you have its card.
Pick: the closer store, unless you are a Costco member.
For atorvastatin, omeprazole, escitalopram, montelukast, pantoprazole and meloxicam, Costco is $6.99 to $10.99, and Walmart's price is not published. Cost Plus Drugs is lower before shipping.
Pick: Costco if you have a card, otherwise ask Walmart for its price.
Costco calls its program a discount card, not insurance, and Walmart says what you pay may differ with your plan. Get your copay and the cash price for the same fill.
Pick: the lower of copay and cash, per drug.
Cash prices sit outside your Part D plan, which prices by its own pharmacy network. Medicare Plan Compare is the official place to see a named drug at a named pharmacy. For negotiated prices, read OmniRx on negotiated prices.
Pick: your plan's price, then these cash prices for comparison.
RxPass is $5 a month on top of Prime for more than 50 listed generics, 8 of the 17 here. It is not available to Medicaid or CHIP members, or for shipping to California and Washington.
Pick: RxPass if you already have Prime and take a listed drug.
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These facts were not stated on the Costco or Walmart pages we read. We make no claim on them.
Costco prices are read from the Member Value Pricing lookup with Generic selected and the form, strength and quantity filters confirmed on each row, using the warehouse pick-up price (home delivery was identical on every row). Walmart tiers are read from the table headers of its PDF ($4 for furosemide, levothyroxine and hydrochlorothiazide; $9 for lisinopril, amlodipine, losartan, sertraline, fluoxetine, citalopram, trazodone and metformin). Costco minus Walmart is taken on the 11 drugs both price: 5 are positive (Costco higher) and 6 negative. The totals are Costco $100.09 and Walmart 3 x $4.00 + 8 x $9.00 = $84.00. The arithmetic is asserted in a small script kept beside the staged page.
The full 17-row comparison with Cost Plus Drugs and 90-tablet prices is on our cheapest pharmacy comparison; the Costco-only view is Costco pharmacy prices; and the Walmart list is in the Walmart $4 list guide and Walmart prescription price lookup. Reuse and embed terms are on our licence page and the pharmacy finder embed. See also our method and the 85 Drug Pricing Statistics.
Not across the board. On the 11 of 17 common generics priced on both, read 26 October 2026, Walmart's published list is $3.99 to $5.99 below Costco on its 3 $4-tier drugs and $0.79 below on lisinopril and citalopram, while Costco is $0.01 to $1.01 below Walmart's $9 tier on the other 6. Added together, the 11 cost $100.09 at Costco and $84.00 at Walmart. Costco is the walk-in price for the 6 drugs Walmart does not list, at $6.99 to $10.99.
Costco says you do not need to be a member to purchase prescriptions (customer service answer CU1540, published August 28, 2023, read October 26, 2026). Its lookup prices are labelled member pricing, and Costco says to show your Costco membership card at the participating pharmacy to receive the discount; what a non-member pays at the counter is not stated on any page we read. The membership fee was not read.
Yes, but not on everything. Walmart's published Prescription Program list, effective 24 March 2025, prices covered generics at $4, $9, $15 or $24 tiers for up to a 30-day supply, with 90-day prices of $10 or $24 on the first two. Of the 11 drugs in our table that Walmart lists, 3 are $4 and 8 are $9. Prices may be higher in some states including California and Minnesota, and the program is not available in North Dakota.
We did not price brand-name drugs, so we cannot say. Costco's lookup can default to the brand: when we searched amlodipine it defaulted to Norvasc at $1,119.71 for 90 tablets. Select Generic, and compare a brand quote from each counter before you fill.
The lookup can default to the brand-name product, and its descriptive subtitle can lag the filter. Make sure Generic is selected, then check the form, strength and quantity filters.
Prescription prices in the United States are set through a documented chain of list prices, pharmacy benefit contracts and federal programs, and the sources below are the primary public records of how that chain works. They are linked so a reader can check a claim here without taking this page's word for it.
This page describes how prescription pricing and discount programs work. It is not medical advice, and what a given person pays depends on their own plan, pharmacy and prescriber.