Bluefly has so far eschewed the private-sale format, but on June 8 will hold its first invitation-only, limited-time sale. The goods will be estate jewelry from Tiffany, Van Cleef & Arpels, Bulgari and Cartier. Prices will be in the thousands, so Bluefly is pulling out all the customer service stops with a dedicated sales person for each item who will complete each order over the phone; a full-refund policy (albeit with a shorter return-time window), and free shipping.

"Vintage and estate is just a wonderful match for consumers today who care about important brands but don’t want to feel guilty about making a purchase," said Bluefly president and chief executive Melissa Payner. Prices are about 20 percent less than new. For example, an estate Cartier Love Bracelet will cost $3,080 rather than $3,850 at regular retail.

It is not unusual for estate jewelry to sell for more of a discount. A quick check of eBay showed what appeared to be the same bracelet available for the "Buy it now!" price of $2,850. But the goods are authentic and not easy to find for Bluefly customers living outside big cities, said Payner. About 100 items, all different, will be in the sale. The move into luxury is new for the retailer. Although Bluefly once sold an $8,000 purse, more typically its high-end designer items range from about $700 to $3,500, said Payner.