For a few minutes early Thursday, some Home Depot online shoppers got an unexpected surprise: their orders were free.

If the orders totaled $101 or less, shoppers didn’t have to pay for what they bought.

It was the result of a promotion for $101 off a specific appliance that, for just a few minutes, was mistakenly applied to every order.

“It doesn’t happen very often,” said Britt Beemer, chairman of America’s Research Group. “They probably have some happy customers.”

Home Depot honored the accidental discount and sent customers an email to assure them their orders would go through, spokesman Stephen Holmes said.

“It was a short, immaterial blip, but we hope it was a nice holiday surprise for a few customers,” Holmes said.

Retailers aren’t legally required to honor obvious mistakes, said Ken Bernhardt, a marketing professor at Georgia State University. Most customers understand if stores correct the error and charge the proper price, he said.

But honoring the discount is good business, as it makes Home Depot look like it’s bending over backwards to serve customers, Bernhardt said.

Customers whose orders totaled $101 or less during the period had the entire order discounted, Holmes said. Those with orders of more than $101 had the discount applied to their total.

The company would not say how many people were affected, or how much it lost, but it said the numbers were not large.

Beemer said Home Depot will likely recover whatever it lost through positive word of mouth. Surprised shoppers tell their friends about unexpected deals, and the retailer often benefits from the good will, said Marshal Cohen, chief retail analyst for NPD Group.

“People love to tell those stories,” he said. “You can’t buy that kind of publicity.”