The site says it will use the investment from Kmart and venture capital firm Softbank to add product categories, develop technology and make acquisitions.
Kmart invested $55 million and Softbank poured $25 million into a second round of financing for BlueLight, which the big discount retailer said is among the largest of the year for any Web retail store.
"We wanted to show that we are the most aggressive, privately funded business-to-consumer plays going," said BlueLight chief executive Mark Goldstein.
Goldstein said much of the $80 million will go to adding new product categories, developing technology and acquiring companies.
The private financing comes as many e-commerce companies are withering. Investors have spurned the sector, and a boatload of online sites have burned through their money or are dangerously close to insolvency.
But some Net units of brick-and-mortar stores have been able to flex their financial muscles in these lean times. Traditional retail giants such as Sears, J.C. Penney and Staples have all made substantial investments in their Internet operations.
BlueLight.com announced last month that it had signed up 3 million subscribers to its free Internet access service. At its more than 2,000 brick-and-mortar stores, Troy, Mich.-based Kmart furnishes the software that allows people to log onto the Internet via BlueLight.
Launched last December, San Francisco-based BlueLight received $62 million from first round investors that included Martha Stewart Living Omnimedia and Softbank.