Matt Colvin stayed home near Chattanooga, preparing for pallets of even more wipes and sanitizer he had ordered, and starting to list them on Amazon. Mr. Colvin said he had posted 300 bottles of hand sanitizer and immediately sold them all for between $8 and $70 each, multiples higher than what he had bought them for. To him, “it was crazy money.” To many others, it was profiteering from a pandemic.

The next day, Amazon pulled his items and thousands of other listings for sanitizer, wipes and face masks. The company suspended some of the sellers behind the listings and warned many others that if they kept running up prices, they’d lose their accounts. EBay soon followed with even stricter measures, prohibiting any U.S. sales of masks or sanitizer.

Now, while millions of people across the country search in vain for hand sanitizer to protect themselves from the spread of the coronavirus, Mr. Colvin is sitting on 17,700 bottles of the stuff with little idea where to sell them.

“It’s been a huge amount of whiplash,” he said.