Mattress Firm Corp., the largest mattress specialty retailer, announced Monday that it is buying New York-based Sleepy's for $780 million, with Mattress Firm taking on $30 million in liabilities as part of the deal. The merged companies will have about 3,500 stores, including the 1,050 stores already owned by Sleepy's, granting it access to the difficult to enter Northeast and mid-Atlantic markets, reported MarketWatch. Now with access to these two markets, Mattress Firm's goal of attaining same-day delivery capability in 95 percent of the country is now within its reach, only missing Wyoming and Alaska.

The news was well-received, with shares of Mattress Firm rising 6.4 percent to $52.52 in after-hours trading Monday.

New Yorkers were excited by the news and mirrored that enthusiasm, according to the New York Post.

"I think Sleepy's was very expensive for customers," said a bedding manufacturer who sells to both chains. "You get a much better value in a Mattress Firm store."

The deal, which is expected to close in August, would allow the merged business to have a 21.2 percent share of the specialty mattress market, industry data from 2014 indicates, according to Consumerist. Once complete, Adam Blank, the current CEO and general counsel of Sleepy's, will join the Mattress Firm executive management team as president of Sleepy's.

In the meantime, Mattress Firm said it would operate under both brands in the "near term."