Can you use a Medicare flex card for grocery delivery (Instacart/Walmart/Amazon)?

Quick answer

Sometimes, but only if your specific Medicare Advantage plan offers a grocery or healthy food benefit and allows online or delivery purchases with that benefit.

A “flex card” is not a standard feature of Original Medicare. It is usually a plan-administered way to access certain Medicare Advantage supplemental benefits. That means the rules depend on your plan, including:

• Which merchants are allowed
• Whether third-party checkout (like Instacart) is allowed
• Whether delivery fees, service fees, tips, and substitutions are eligible

What a “Medicare flex card” usually means

Many people use “flex card” to describe a prepaid card tied to one or more Medicare Advantage supplemental benefits. Depending on your plan, the card might be used for:

• Over-the-counter health items
• A “food and produce” or “healthy food” allowance
• Other approved supplemental benefits

Important details to keep in mind:

• Names are not standardized. Two plans can use the same phrase (like “flex card”) but have very different rules.
• The card is usually restricted. It often works only for certain item categories and only at certain merchants.
• You may have one card with multiple “wallets.” For example, your plan might separate “OTC” funds from “healthy food” funds, even if they sit on one physical card.

Why grocery delivery is harder than in-store purchases

Grocery delivery adds extra moving parts that can trigger a decline, even when your benefit is active.

Merchant rules can block delivery platforms

Many flex card benefits are designed to work only at approved retailers. Delivery platforms can complicate this because payment may be processed by:

• The grocery store itself
• The delivery platform
• A payment processor tied to the platform

Even if you are buying groceries from a store you recognize, the transaction might not look like that store to your benefit system.

Delivery orders often include “non-grocery” charges

Delivery purchases often include separate line items that your plan may treat differently, such as:

• Delivery fees
• Service fees
• Priority or express fees
• Driver tips
• Bag fees
• Taxes (rules vary by state and by plan benefit design)

If your plan covers only eligible grocery items, you may need a second payment method for the rest.

Substitutions can change what you are actually buying

Substitutions are a common reason for surprise declines. A shopper might replace an eligible item with something that your plan does not allow.

Examples that can cause problems:

• Brand or size changes that fall outside your plan’s eligible list
• Substituting prepared foods for basic ingredients
• Replacing a low-sodium option with a regular version, or vice versa
• Substituting snack foods or sweets for a healthier item you selected

Instacart: what to expect with a flex card

Instacart is one of the most common places people try to use a grocery benefit, and also one of the most likely places to run into merchant and fee issues.

What usually determines whether it works

Your flex card may work on Instacart only if your plan allows:

• Online grocery purchasing for your food benefit
• Purchases through Instacart specifically, not only through a store’s own website
• The specific retailer you are ordering from

How to reduce the chance of a decline

Before a full order, consider a small test purchase. Then tighten up the parts that cause the most trouble:

• Choose a retailer your plan lists as approved for the food benefit
• Avoid add-ons like express delivery if you can
• Keep substitutions under control
• Have a backup payment method ready for fees or ineligible items

Substitutions on Instacart: practical tips

To limit substitution problems:

• Turn off substitutions for items you suspect might be restricted
• Add substitution notes like “Only replace with fresh or frozen vegetables”
• If your plan is strict, avoid categories like prepared foods and desserts unless you know they are eligible

Walmart grocery delivery or pickup: what to expect

Walmart can work for some people, but the deciding factor is still your plan’s rules.

Online vs in-store rules matter

Some plans allow grocery benefits:

• In store only
• Online only through specific portals
• Online at participating retailers, but only when checkout is processed in a certain way

If your plan is in-store only, you might find that:

• The card works at a physical register
• The same card does not work on Walmart’s app or website

Fees to watch for

Walmart orders can include:

• Delivery fees
• Membership-related fees
• Tips
• Substitution differences between what you selected and what you received

If your card benefit covers only eligible food items, plan on using a second payment method for any fees your benefit does not cover.

Amazon grocery: what to expect

Amazon grocery shopping can include Amazon Fresh and grocery delivery from other partners, plus groceries from Whole Foods in some areas.

A flex card may work only if:

• Your plan lists Amazon (or the relevant Amazon grocery service) as an approved merchant for the food benefit
• Your plan allows online grocery transactions for that benefit category
• The items you choose match your plan’s eligible food rules

If your plan does not explicitly support it, Amazon is a common place to see declines because the transaction may not match the merchant rules built into your benefit.

How to confirm your plan’s rules before you place a delivery order

This is the step that saves the most frustration. A “flex card” is only as useful as its rulebook.

Step 1: Identify what benefit you actually have

Ask your plan (or check your plan documents) whether your card funds are for:

• OTC items
• Food and produce or healthy groceries
• A combined benefit with separate categories

Step 2: Confirm which merchants are allowed for the grocery benefit

Ask for a list of participating retailers and whether delivery platforms are included.

Helpful questions:

• “Can I use my grocery or food benefit online?”
• “If yes, which websites or apps are approved?”
• “Is Instacart approved, or only the store’s own website?”
• “Is Walmart.com approved for my plan, or only Walmart stores?”
• “Is Amazon or Amazon Fresh approved for my plan?”

Step 3: Confirm what happens with delivery fees and tips

Ask your plan:

• “Does my food benefit cover delivery fees or service fees?”
• “If fees are not covered, can I split payment at checkout?”
• “Will a tip cause the whole transaction to decline, or only the tip portion?”

Step 4: Ask how substitutions are handled

Ask:

• “If an item is substituted with an ineligible item, will it be declined automatically?”
• “Will the rest of the order still go through?”
• “What is the best way to avoid declined substitutions?”

Delivery fees, tips, and why checkout may still fail

Even when your plan allows grocery delivery, fees are often the breaking point.

Common outcomes include:

• Eligible groceries are approved, but delivery fees require a second payment method
• Some charges are approved and others are declined, leading to a partial order or an interrupted checkout
• The platform tries to authorize a higher amount up front (to cover substitutions or tips), and that authorization fails if your benefit balance is too low

A simple approach that often helps:

• Keep the grocery cart clearly “food only”
• Use a second payment method for fees and tips if your plan allows split payment
• Leave extra room in your balance for substitutions and authorization holds

Substitution problems and how to avoid surprises

Substitutions are meant to help you get your groceries, but they can work against strict benefit rules.

Ways to reduce issues:

• Choose “no substitutions” for categories that are commonly restricted in your plan
• Add a note: “Substitute only with the same type of item (for example, fresh produce only)”
• Avoid edge categories unless you know your plan allows them, such as prepared foods and snack foods
• Order earlier in the day when more items are in stock, which can reduce substitutions

Common problems and what to do next

“My card was declined”

Most common reasons include:

• The merchant is not approved for your benefit
• Online purchases are not allowed for your benefit
• One or more items are not eligible
• Fees or tips are included and your plan does not cover them
• Your balance is too low, not loaded yet, or expired
• Your card has multiple benefit categories and the purchase is routing to the wrong category

A practical next step is to call the number on the back of the card and ask:

• “Was the decline because of the merchant, the items, or fees?”
• “Is online grocery delivery allowed for my benefit?”
• “Which retailers and platforms are approved?”

“Some items went through but others did not”

This often points to item-level restrictions. If you are helping an older adult, it can help to:

• Save the receipt and the declined items list
• Ask for the plan’s eligible items guidance for the grocery benefit
• Try a different brand or size of the same item

Related Understood Care resources

• https://understoodcare.com/uc-articles/healthy-food-benefit-vs-otc-card-whats-the-difference
• https://understoodcare.com/uc-articles/deep-plan-by-plan-comparisons-of-grocery-benefits
• https://understoodcare.com/uc-articles/flex-cards-and-grocery-benefits-that-can-also-pay-rent-or-utilities
• https://understoodcare.com/articles‍

FAQ

• Can I use a Medicare flex card to pay for Instacart grocery delivery? It depends on whether your Medicare Advantage plan allows grocery benefits to be used through Instacart specifically, and whether fees and substitutions follow your plan’s eligibility rules.
• Can I use a Medicare flex card on Walmart grocery delivery or pickup? Some plans allow it and some do not. A common issue is that a plan may allow Walmart in-store purchases but not Walmart.com or app-based checkout.
• Can I use a Medicare flex card for Amazon Fresh or Amazon grocery delivery? Only if your plan lists Amazon’s grocery services as approved merchants for your grocery or food benefit and allows online transactions for that benefit category.
• Do Medicare flex cards cover delivery fees, service fees, or tips? Often the grocery allowance covers eligible food items only. Fees and tips may require another payment method, depending on your plan.
• What happens if Instacart or Walmart substitutes an item that is not eligible? The substituted item may be declined, and you may be asked to pay out of pocket or remove it. Some checkouts may fail if the platform cannot complete payment as a split transaction.
• Is a “Medicare flex card” part of Original Medicare? No. Flex cards are typically tied to supplemental benefits offered by certain Medicare Advantage plans, not Original Medicare.

References

• https://www.medicare.gov/publications/12026-understanding-medicare-advantage-plans.pdf Medicare
• https://www.medicare.gov/basics/get-started-with-medicare/get-more-coverage/your-coverage-options Medicare
• https://www.medicare.gov/plan-compare/ Medicare
• https://www.cms.gov/medicare/health-plans/healthplansgeninfo/downloads/supplemental_benefits_chronically_ill_hpms_042419.pdf CMS
• https://www.cms.gov/files/document/updated-guidance-medicare-advantage-organizations-5132020.pdf CMS
• https://www.cms.gov/newsroom/fact-sheets/2019-medicare-advantage-and-part-d-rate-announcement-and-call-letter