If you forgot something on your grocery list or just need to pick something up in a pinch, drugstores may be your go-to. There’s usually one around the corner, and you can zip in and out quickly.

But there’s a cost for convenience. “Drugstores are now competing with huge chains and online options,” explains Benjamin Glaser, features editor with DealNews. “They charge a premium for those who can't wait to compare prices or get a delivery.”

We did some poking around to see what types of items at drugstores have the greatest markup. To keep things consistent, we compared the costs of regular-priced items online at CVS and Walgreens against some of the major big box retailers like Target, Wal-Mart, and Costco. Just keep in mind, some prices may have changed since the research for this story was completed (the week of May 21, 2017).

Here are 7 things you should never buy at a drugstore: