By Esme Murphy

By Esme Murphy, WCCO-TV

READ MORE: Good Question: How Do Trees Know When To Bloom?

MINNEAPOLIS (WCCO) — If you think you are paying more for prescription drugs, you are right. In 1980, the average non-generic prescription cost $10. This year the average cash price is $180.

However, what WCCO-TV’s Esme Murphy found is that the price for a prescription varies dramatically depending on which pharmacy chain you shop at.

And WCCO found a little-known regulation that allows everyone to take advantage of a store that consistently has the lowest prices.

Even with insurance, the federal government estimates that Americans now spend $238 billion on prescription drugs. That’s more than double a decade ago. But WCCO found how much you spend depends on where you shop.

For example, the full cash price of a 30-day supply of Divalproex DR, a generic anti-seizure medication, ranged from $94 at Walgreens to $14.27 at Costco.

As for the other pharmacies, when it comes to Divalproex DR, CVS was the second highest price at $92.59. Target was next at $90. Wal-Mart charged $56.84 and Sam’s Club was next at $47.46.

At an AARP roundtable, 85-year-old Scotty Scattarelli, a diabetic, shares how she saved more than $100 a month.

“I ended up going to Costco. That was the cheapest place at the time,” she said.

But Scattarelli is not a Costco member. She has discovered a little-known state law that can save you big bucks on prescription drugs.

It costs $50 a year to join Costco to shop there, but under state law,anyone can shop at Costco’s pharmacy, even if you are not a member.

The law applies to all wholesale clubs, including Sam’s Club, but it’s Costco that WCCO found consistently delivers the best pharmacy deals.

Of the 11 generic and non-generic drugs WCCO checked, Costco had the lowest price on six medications and the second lowest on four. Costco did not stock one of the medications.

Walgreens offers two set of prices on its medications. One set is among the highest prices WCCO found and the other set is among the lowest.

READ MORE: Minnesota Companies Mining Gold From Nostalgia For Decades Gone By

How can that be? The low prices are for members of Walgreens’ prescription savings club which costs $20 a year.

Marion Zampf, a 35-year-old mother of two, suffers from Lupus and has to take up to four medications a day. She said no one at Walgreens ever told her about the club.

During her last pregnancy, she was put on Warfarin, a generic blood thinner. The price at Walgreens for a month’s supply for non-club members is $29. For club members, it was $10, which is a $19 difference.

“I don’t think it’s fair at all,” said Zampf.

Remember the Walgreens price for the anti-seizure medication Divalproex DR? The non-club price is $94 while the club price is $64.49, which is more than a $29 difference.

For Viagra, the non-club price for 30 pills is $676 while the club price is $594. That’s a $77 difference.

Zampf left Walgreens and now gets her prescriptions by mail order. That’s not a guarantee, however, according to Professor Stephen Schondelmeyer, a nationally-known expert on drug pricing at the University of Minnesota.

“Don’t just assume that mail order pharmacies are cheaper. We found cases where they’re not; where it cost more than the retail pharmacy,” he said.

Prescription prices vary so greatly that consumers might be tempted to shop different pharmacies for their different medication. And while they will almost certainly save money that way, it could also prove dangerous.

“If you start dividing your prescriptions among three or four or five pharmacies, then the pharmacists won’t know all the medications you are on and can’t help avoid safety problems and drug interactions,” said Schondelmeyer.

So, what’s a consumer to do?

Shondelmeyer said asking for a lower price from your pharmacist usually works.

“If a given community pharmacist knows you have a lower price from somewhere else, they usually will match that or meet that. They can’t always do that but usually they will,” he said.

WCCO reached out to all the companies mentioned in this report. You can view their responses in the links below. And if you would like to see a spreadsheet of the research into drug costs, click on the link below.

MORE NEWS: After Her Kids Were Hacked, Cybersecurity Engineer Writes Children's Book

Drug Price Comparisons (PDF)
Walgreens Statement On Drug Price Comparisons (PDF)
CVS Statement On Drug Price Comparisons (PDF)
Target Statement On Drug Price Comparisons (PDF)

Esme Murphy