You know that moment at the pharmacy counter when they tell you the price and you just stare at the number for a second, then hand over your card trying not to look fazed? I had that moment with a thirty-day supply of a generic medication that cost me a hundred and forty dollars with insurance.

I went home, spent twenty minutes online, and found the same prescription at a different pharmacy three blocks away for forty-one dollars. Same drug. Same dosage. Same insurance. I had been overpaying by a hundred dollars a month for over a year.

Here’s how to not do what I did.

Check GoodRx before you fill anything

GoodRx is a free website and app that shows you the cash price of your prescription at every pharmacy near you. Sometimes the GoodRx price is lower than your insurance copay. You just show the coupon on your phone and the pharmacy applies it. No registration, no fee.

I now check GoodRx for every new prescription before I fill it. Takes thirty seconds. I’ve saved money on probably two-thirds of my prescriptions, and on one of them the GoodRx price was actually better than my insurance.

Ask for the cash price

Pharmacies are not allowed to voluntarily tell you that paying cash might be cheaper than using your insurance — it’s often prohibited by their contracts with insurance companies. You have to ask. A simple “what’s the cash price for this?” can save you a surprising amount.

I had a pharmacist once lean in and whisper “off the record, it’s twenty dollars cheaper if you don’t use your insurance.” She wasn’t supposed to tell me. I appreciated it.

Other ways to cut costs

• Cost Plus Drugs: Mark Cuban’s online pharmacy sells many generic medications at cost plus a fixed markup. No insurance needed. Prices are transparent and often significantly lower than retail pharmacies.
• 90-day supply: A three-month supply almost always costs less per pill than a 30-day supply. If it’s a medication you take long-term and your doctor is willing to write a 90-day prescription, this is an easy win.
• Higher dose, split the pill: Some medications cost the same whether you get 10mg or 20mg tablets. If your doctor approves, getting the higher dose and splitting the tablet with a pill splitter can cut your cost in half. Do not do this without your doctor’s explicit OK — some medications are not safe to split.
• Manufacturer coupons: For brand-name drugs, check the manufacturer’s website. Many offer savings cards that reduce your copay to as low as $10 or $25.

What not to do

Don’t order from unverified online pharmacies outside the US to save money. Counterfeit medications are a real problem. Don’t skip doses to stretch your supply — that can make your condition worse and lead to more expensive treatment later.

I wish someone had told me about GoodRx years ago. I’d have about a thousand more dollars in my bank account. This is one of those things that should be common knowledge and somehow isn’t.