CORRECTION

An article in the Business section Thursday had the wrong price for mailing a postcard. The correct price is 26 cents.

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Being square this holiday season will cost more than just your hipster reputation.

After years of looking the other way, the U.S. Postal Service is charging more this year for square envelopes of any size.

How much more depends on how big. A rectangular envelope, 5 1/2 by 8 1/2, gets the usual 41-cent first-class stamp. But one of those trendy square 6 1/2-inch greeting cards will cost you 58 cents. If your list is long, it adds up.

The surcharge has long been a possibility. Those square envelopes can't be read by the postal machines and so must be processed by hand, which costs more. When the agency started its new shape-based pricing system this year, letters in square envelopes started to cost more. But it has taken the holidays with all those Christmas, Kwanzaa and Hanukkah cards to make the change resonate with people.

Mindy Hiteshue, a business manager at Conservation Network in Raleigh, said the extra cost isn't worth it.

"I would never buy them," she said as she left the Post Office in downtown Raleigh.

So what size do the machines like?

Carl A. Walton, a spokesman for the U.S. Postal Service, said that would be any envelope that's 11 1/2 inches long and 6 1/8 inches high -- or smaller, as long as it's not square. Anything outside of those dimensions could be considered "nonmachinable" and charged extra postage.

A surcharge is also charged for envelopes with clasps, strings, button or other closures; and letters that are rigid or enclosed in plastic material. To learn more about rates and extra services, go to www.usps.com/rates /extra-services-rates.htm.

There are cheaper options.

For instance, a postcard typically costs 26 cents to mail.

Or you could send a card by e-mail. Hallmark offers the majority of its e-cards for free, said Julie O'Dell, a Hallmark spokeswoman. If you want to send a Hallmark.com e-card with a personalized photo, it will cost from $1.59 to $2.99 per card.

AmericanGreetings offers a limited number of free e-cards, said Sally Babcock, senior vice president and general manager of AmericanGreetings.com. A year's subscription, $13.99 for most of its e-cards, lets you send as many cards as you like, including talking cards and photo cards.