We've told you before about the option of buying and selling gift cards online, which is a  alternative to dispense with cards for stores that you aren't likely to use, or score a greater discount for those you plan to patronize.

I was a little leery, however, because of the time delay for cards to be mailed to you --- I don't necessarily plan my shopping trips two weeks in advance. And, there's the potential that the card wouldn't actually carry the promised value --- though some sites offer a money-back guarantee.

But I didn't realize until I read the comments on this Consumerist post that some sites, such as Plastic Jungle and Cardpool, allow you to buy and sell cards electronically for certain vendors, such as Target.com.

That means when you're ready to buy something from an online retailer, search for a discounted electronic gift card and apply that value to your purchase to get even more savings. Gift Card Granny is one aggregating site that posts offers from different gift card resellers to let you compare what's available.

Plastic Jungle will allow you to sell gift cards from a list of 36 merchants (including Bed Bath and Beyond, Gap and Macys) for instant Amazon.com credits. With Cardpool, you can transfer the value of your card to the site electronically and they'll send you a check within 24 hours.

But the limited number of vendors participating with each site differs, so if you can't sell a card electronically at one, be sure to check the other. For example, you can sell a Cheesecake Factory card electronically at Cardpool, but Plastic Jungle will accept Best Western.