Large mattress retailer Mattress Firm has filed for Chapter 11 bankruptcy protection and plans to close hundreds of stores — the result in part of being upended by online mattress startups that sell products like bed-in-a-box.

“The cost to start an online mattress company is next to zero,” said Jeffrey Galak, a marketing professor at Carnegie Mellon University. “Few of the companies that are selling online actually manufacture their own mattresses. What they do is they find a mattress manufacturer or somewhere overseas, they slap their branding and their logo on there and then they promote the heck out of it as much as they can.”

They promote on social media feeds — and it’s working for them, said Charles Lindsey, a business professor at the University of Buffalo. He said these startups now have about 12 percent of the nearly $15 billion retail mattress market. These online companies offer convenience.

“The mattress is compressed and vacuum sealed. They ship it for free. Pretty easy-peasy,” he said.

More often than not, younger shoppers are buying mattresses online, said Ryan Trainer, president of the International Sleep Products Association. On average, people replace a mattress every 10 years — for 19- to 35-year-olds, that’s more like every six years.

“Younger consumers have been kind of conditioned to replace their phone after a couple of years regardless of whether the phone is still functional or not,” Trainer said. “They’re wanting to get the latest and greatest bells and whistles with their product. And I think they’re carrying that over to other durable goods such as mattresses.”

And it isn’t enough for the online startups to stay online — some of the bigger companies are moving into brick and mortar stores so customers can try them out the old fashioned way — by lying down.