PHILADELPHIA (CBS) - Some major retailers have re-introduced the concept of “layaway” for your upcoming holiday purchases.

Is it a good idea for shoppers?

David Allan, an associate professor of marketing at St. Joseph’s University, says for some shoppers, putting a purchase on layaway – that is putting the item aside and making payments over time on it – makes sense.

“The reason why it was originally created is the same reason why it’s having a re-birth. It’s because it’s a practical, fundamental way to be able to purchase something you can’t afford right away, starting today.”

Allan says stores like Wal-Mart, K-Mart and Toys ‘R’ Us have specific rules regarding the size of the purchase and how soon it has to be paid off. He says read the agreement thoroughly before signing.

And while Allan concedes merchandise you might buy now and put on layaway could end up on sale on “Black Friday” or in early December, you run the risk quantities will be limited.

He says a layaway is a contract between you and the retailer that the item will be there at the agreed upon price, once you’ve paid it off.

Reported by Mark Abrams, KYW Newsradio 1060