Cost Plus Drugs offers low-cost generic prescription drugs with a transparent pricing system. If you have Medicare, you can still use it to save money by paying out of pocket.
But there are two important caveats: Money you spend at Cost Plus Drugs won’t count toward your deductible, and you have to maintain Medicare Part D prescription drug coverage if you want to avoid a late penalty.
How does Cost Plus Drugs work?
The Mark Cuban Cost Plus Drug Co., or Cost Plus Drugs, is an online pharmacy that sells over 2,300 generic medications and select brand-name medications. Available medications and their prices are listed on the company’s website. After your doctor sends a prescription to Cost Plus Drugs, you check out online and the medications are shipped to you.
Cost Plus Drugs is notable for offering cheap medications with transparent pricing. “Every product we sell is priced exactly the same way: our cost plus 15%, plus the pharmacy fee, if any,” the company's website says about its pricing model.
Cost Plus Drugs offers this example for a 30-count supply of 400 milligrams of Imatinib, a cancer drug:
- Manufacturing cost: $25.65.
- 15% markup: $3.85.
- Pharmacy labor (the “pharmacy fee”): $5.
- Shipping: $5.25.
Including the shipping, that would be $39.75 per month. At a major retail pharmacy, Imatinib can cost well over $100 per month, even when covered by a Medicare prescription drug plan.
Can you use Cost Plus Drugs if you have Medicare?
Medicare members can use Cost Plus Drugs, but your Medicare plan won’t be involved. Cost Plus Drugs doesn’t bill Medicare, whether you have a stand-alone Medicare Part D plan or a Medicare Advantage plan with prescription drug coverage. You’d have to pay for medications from Cost Plus Drugs out of your own pocket, but it may be worth it.
Compare Medicare Part D Plans
| Insurance company | NerdWallet rating | Out-of-pocket costs | Member experience |
|---|---|---|---|
| Lower than average | 3 (Average) | ||
| Varies | 3.5 (Above average) | ||
| Average | 2 (Below average) | ||
| Average | 2.29 (Below average) |
How Cost Plus Drugs affects your Medicare Part D coverage
You don’t get any credit toward your Part D deductible when you fill a prescription through Cost Plus Drugs. You only meet the Part D deductible by paying for drugs your plan is covering, and Cost Plus Drugs doesn’t bill Medicare Part D plans.
You can still meet your Medicare Part D deductible by paying for other drugs your plan covers. For example, Cost Plus Drugs doesn’t sell most brand-name drugs, so you could fill brand-name prescriptions through your Part D plan and meet the deductible that way.
If you fill most or all of your prescriptions through Cost Plus Drugs, though, you’re potentially missing out on a lot of credit toward your deductible. You still have to pay your premiums, but until you hit the deductible, your Medicare Part D plan doesn’t pay for your drugs.
Why you still need Medicare Part D coverage
If you take mostly or entirely generic drugs, it might be tempting to use Cost Plus Drugs and go without Medicare Part D coverage. However, you could face the Medicare Part D late enrollment penalty. You’ll need to have either Medicare Part D or another kind of creditable coverage (such as an employer plan) that’s at least as good as Medicare Part D to avoid being penalized.
Even if you could save money by using Cost Plus Drugs and skipping Medicare Part D, you’d face the Part D penalty if you ever sign up (or sign back up) for Medicare Part D.
The Medicare Part D late enrollment penalty is 1% of the national base beneficiary premium — $38.99 in 2026 — for each full month that you didn’t have qualifying prescription drug coverage, rounded to the nearest 10 cents.
For example, if you went without coverage for two years, or 24 months, your monthly penalty would be 24% of $38.99, or $9.40 (rounded to the nearest 10 cents), in 2026. That amount is added to your premiums every month. It would go up or down in subsequent years based on the national base beneficiary premium, but it doesn’t ever go away.
Shopping for Medicare Part D plans? We have you covered.
| MEDICARE PART D covers outpatient prescription drugs for people on Medicare. Compare options from our Medicare Part D roundup. | |
| Best for low premiums | Best for low out-of-pocket costs |
| Best for generic drugs | Best for low deductibles |
Is Cost Plus Drugs a good idea for Medicare beneficiaries?
Cost Plus Drugs could offer savings on generic drugs, even for people who are already covered by a Medicare prescription drug plan.
However, there are also some downsides to using Cost Plus Drugs on Medicare:
- Prescriptions filled through Cost Plus Drugs don’t count toward the Medicare Part D deductible.
- Cost Plus Drugs doesn’t sell most brand-name drugs (which tend to be the most expensive).
- You’d owe steep and permanent penalties for going without Medicare Part D coverage, so it’s not a good idea to drop your Part D plan, even if you can get cheaper medication from Cost Plus Drugs.
In short, if you take a drug with a generic version, it’s worth checking the price on Cost Plus Drugs to see whether you could potentially save money. But Cost Plus Drugs isn’t a replacement for Medicare Part D.
