By Amy E. Feldman

PHILADELPHIA (CBS) - Along with explosive growth in online holiday shopping comes a new trend. Online layaway.

Ah Thanksgiving. A time to give thanks – for the online merchants who are happy to take your money. Online purchases on Thanksgiving Day in preparation for the holiday were up 39% last year. One more growing trend: online layaway.

Before you do it, you should know that there’s no federal law that governs layaway plans. Consumer protection laws vary by state, and as you can imagine there is great variation on the legitimacy of those online layaways.

Look for details on: how much it costs to open an online layaway. Many charge $5 or $10 which can be a big percent of the total owed. Also, find out if there is a fee or a penalty for missed or late payments: Will your contract be cancelled? Will the merchandise be returned to inventory? And the refund policy: If you decide you don’t want the merchandise after you’ve made some or all the payments, can you get a refund? In cash or just in credit?

So much to digest, in addition to that turkey.