But Consumer Reports discovered just because you're buying generic doesn't mean you're getting a great price, and it is best to shop around.
Atorvastatin is the generic name for Lipitor - one of the most widely prescribed drugs in America.
So Consumer Reports checked out prices of the cholesterol medication at more than 200 pharmacies - including Walgreens, CVS, Target, Walmart, and Costco.
They also checked out independent and supermarket pharmacies, and online.
Lisa Gill, of Consumer Reports, says, "We found that prices for atorvastatin varied tremendously depending on where you got the prescription filled."
Prices were generally cheaper in suburban and rural areas than in big cities.
And among chain stores, atorvastatin cost the most at CVS - 150 dollars for a month's supply.
Costco had the best price - 17 dollars.
You don't have to be a Costco member to use its pharmacy.
In addition to atorvastatin, Consumer Reports found it also had low prices for other blockbuster drugs that have recently gone generic.
Those drugs were the generics of Actos for type 2 diabetes ? Lexapro for depression ? Singulair for asthma ? and Plavix, a blood thinner.
"So with the five prescription drugs that we checked, CVS tended to be the most expensive. RiteAid and Target weren't much cheaper," she says.
As for Walmart, it fell somewhere in the middle of the pack.
But two online retailers also offered very good deals -Healthwarehouse and FamilyMeds.
Gill says, "No matter what drug you're prescribed, don't be afraid to talk to your doctor about costs. You may be able to get a lower-priced alternative to treat your condition."
It is always good to ask.
CVS tells ABC News that "pricing surveys don't always reflect what most customers pay given various value, discount, and third-party insurance programs."
Consumer Reports recommends asking for the best prices, and ask if the pharmacy can work with you.
This typically works better at independent pharmacies. But again, it never hurts to ask.