Metformin costs $4–$15 per month without insurance — making it one of the most affordable prescription medications available. With Walmart's $4 generic drug list or a free RxDiff coupon at any major pharmacy, most patients pay $4–$10 per month for a standard supply.
This guide covers metformin prices by dose and pharmacy, the difference between IR and ER formulations, and how to confirm the lowest price before filling. Compare current metformin prices at pharmacies near you on RxDiff.
Metformin costs $4–$15 per month without insurance at most pharmacies — and often less with a free coupon or the Walmart $4 generic list. Walmart's $4 generic program covers metformin 500 mg and 1000 mg immediate-release at $4 for a 30-day supply and $10 for a 90-day supply. No membership, no coupon, and no insurance needed for the Walmart $4 price.
Metformin is the most widely prescribed first-line medication for type 2 diabetes in the U.S. It has been generic for decades and is produced by dozens of manufacturers — which is why the price is so low. No manufacturer patient assistance program exists for metformin because it is already extremely affordable in its generic form.
| Medication | Walmart $4 List | Costco | CVS | With RxDiff Coupon |
|---|---|---|---|---|
| Metformin IR 500mg 30ct | $4 | $4–$6 | $10–$20 | $4–$8 |
| Metformin IR 1000mg 30ct | $4 | $4–$8 | $10–$25 | $4–$10 |
| Metformin IR 500mg 90ct | $10 | $8–$14 | $20–$50 | $8–$20 |
| Metformin ER 500mg 30ct | Check state list | $6–$12 | $15–$35 | $5–$15 |
| Metformin ER 1000mg 30ct | Check state list | $8–$15 | $20–$40 | $8–$18 |
Walmart's $4 generic list is often the cheapest option — no coupon required. However, a free RxDiff or GoodRx coupon at Costco sometimes delivers a comparable or lower price for specific doses and quantities, especially on 90-day fills. Always compare on RxDiff before filling — prices vary by exact dose, form, and quantity.
Metformin IR (immediate-release) is taken 2–3 times daily with meals. It's the most affordable form and widely available on the Walmart $4 list. Metformin ER (extended-release) is taken once or twice daily and may cause fewer gastrointestinal side effects — particularly nausea and diarrhea — for some patients. Metformin ER typically costs more than IR. Your healthcare provider recommends the appropriate formulation based on your tolerability and blood sugar management needs.
If you're starting metformin and cost is a priority, discuss immediate-release metformin with your healthcare provider. Metformin IR is equally effective for blood sugar management for most patients with type 2 diabetes — the only meaningful difference is dosing frequency and GI tolerability, not clinical efficacy. If GI side effects are bothersome on IR, your prescriber may switch you to ER at that point.
Yes — metformin 500 mg and 1000 mg immediate-release tablets are commonly on Walmart's $4 generic drug list in most U.S. states. A 90-day supply costs $10. The extended-release (ER) formulation may or may not be on the $4 list depending on your state — confirm with your local Walmart pharmacy before filling.
To use the Walmart $4 program: bring your prescription to any Walmart pharmacy or Neighborhood Market pharmacy and ask for $4 generic pricing. No enrollment, no membership, and no coupon is required. The pharmacist checks whether your specific dose qualifies for the $4 price.
Metformin is also available as a combination pill paired with sitagliptin — sold as Janumet (sitagliptin/metformin) and Janumet XR (sitagliptin/metformin ER). These combination medications treat type 2 diabetes using two different mechanisms in one daily pill. Sitagliptin/metformin price is significantly higher than plain metformin — typically $550–$600 per month without insurance.
If your prescriber wrote for Janumet, ask whether plain metformin plus a separate sitagliptin generic would cost less. Sitagliptin/metformin ER cost follows the same pattern — the ER version of the combination is similarly priced to the immediate-release form. Generic sitagliptin/metformin is now available following patent expiration, which has reduced costs. Compare sitagliptin/metformin cost and all metformin combination options on RxDiff before filling.
Trusted platforms for comparing diabetes medication prices include RxDiff, GoodRx, and the Walmart $4 generic program. Find the cheapest metformin price at pharmacies near you — free on RxDiff.
Compare Metformin Prices on RxDiff →Many immediate-release prescriptions cost around $4-$15, but strength, formulation, quantity, and pharmacy determine the actual price.
Selected 500 mg and 1,000 mg immediate-release prescriptions may qualify. Confirm the exact formulation and quantity with the pharmacy.
Only your prescriber or pharmacist should guide a formulation or dose change. Extended-release and immediate-release products are not automatically interchangeable.
For authoritative information, see the ADA Standards of Medical Care in Diabetes. The American Diabetes Association Standards of Medical Care in Diabetes recommends metformin as the preferred initial pharmacologic agent for most adults with type 2 diabetes due to its efficacy, safety, tolerability, and low cost.
Medical Disclaimer: This content is for informational purposes only. Drug prices change frequently — always verify current pricing at your pharmacy before filling. Consult your healthcare provider or pharmacist about your specific medications.