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The Cheapest Ways to Get Flea, Tick and Heartworm Meds

October 31, 2026 · Sean Arenas

Flea, tick and heartworm prevention is one of the few pet costs that comes every single month, for the whole life of your pet. It’s also one of the easiest to lower without lowering the care. Here’s where the savings are.

One rule first: never use a dog product on a cat. Some dog flea treatments contain permethrin, which can be deadly to cats. And never split a large-dog dose between pets unless your vet says that product allows it.

1. Ask for the prescription, then shop it

Many preventives need a prescription, but that doesn’t mean you have to buy them where you got the prescription. Ask your vet for a written prescription, or to approve one for the pharmacy you choose. Then compare:

• Costco pharmacies fill pet prescriptions at member pricing, and the pharmacist can transfer the prescription from your vet.
• Walmart Pet Pharmacy lets you manage your pet’s prescriptions next to your own.
• Amazon fills pet prescriptions through Vetsource pharmacies, after your vet approves.
• GoodRx coupons can lower the price of medicines that are also sold for people, at a regular pharmacy. They won’t help with vet-only preventives like Simparica Trio, so use GoodRx for the human-equivalent medicines your pet takes.

Also ask your vet whether their own online store matches outside prices. Many clinics have one, and it keeps your records in one place.

2. Compare the cost per month

A 6- or 12-month pack costs more at checkout but often less per dose. Divide the price by the number of months it covers, then compare. If paying for a large pack at once would leave you short, a smaller pack you can keep up with is the better deal.

3. Check for a manufacturer rebate

The big manufacturers run rebates on some of their preventives when you buy them at your vet, and many people never claim them. You upload or mail the invoice and get money back or points:

• Merck: Bravecto, Sentinel and Tri-Heart Plus
• Elanco: Credelio, Interceptor Plus and others
• Zoetis Petcare Rewards: Simparica Trio, Revolution Plus and others, as points toward future vet visits

Each offer has its own rules: which products and pack sizes count, where you have to buy, and a deadline (some are 30 days, some 90). Check the current offer before you buy, and keep the itemized invoice.

4. Look for a lower-cost preventive care clinic

If your pet is healthy and needs vaccines, a heartworm test or preventives, in-store clinics can cost less than a full vet visit: Vetco at Petco, ShotVet pop-ups at partner stores, and Tractor Supply PetVet. Many skip the office-visit fee, but tests and services still have their own prices, so check before you go. Some prescriptions may still need your regular vet.

Dogs should have a heartworm test before starting prevention, before restarting after a gap, and once a year after that, even when they never miss a dose.

For a pet that’s sick, see your regular vet. These clinics are for prevention.

5. Buy only from a real pharmacy

Deep discounts from unfamiliar websites can mean expired, counterfeit or foreign-labeled products. If a site sells prescription preventives without asking for a prescription, walk away. Look for a pharmacy that checks with your vet.

6. Before you skip a dose because of cost, talk to your vet

Treating heartworm disease costs far more than preventing it, and it’s hard on your dog. If preventives are getting out of reach, tell your vet before you stop. They may be able to suggest a lower-cost product that still protects your pet. The Save on Pet Care page lists more ways to cut the cost of food, supplies and routine care.

Every program linked here was checked on its official website on the date shown on our Save on Pet Care page. Offers change, so confirm the details before you buy.

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