If you think about it, you probably have been bartering longer than you’ve been using money. Remember dumping out your trick-or-treat bag and swapping Smarties for Sixlets? Remember using your friendship as a trade? You know, like when your sister was going to the mall and you’d say, “Can I come? Ooh, please let me come! I’ll be your best friend!”

Bartering has a rich history in the United States. Colonists in the 17th and 18th centuries were all, “Hey, I’ll trade you this beaver pelt for eight pounds of that gun powder.” During the Great Depression, swapping made a comeback. Nobody had any money, so people engaged in what is now known as “survival bartering,” trading things they had (potatoes, matches, towels) for things they needed (medicine, milk, soap). A less desperate, more social form of bartering came about in the deep recession of the 1980s.

No big surprise, bartering is back in vogue during these hard times. Businesses and charities are doing more “in-kind” business trades than ever. And as cash becomes less expendable, there are a ton of new Web sites capitalizing on consumers’ newfound respect for the value of goods they and others have laying around.

Some, such as SwapAce.com, Rehash. com and SwapTree.com, require that you exchange your item directly with another user for his or her item. That means you’ll have to find someone whose needs match up with your “junk” and vice versa.

Others—like SwapItGreen.com, BarterBee.com and SwapJunkies. com— use a points system, in which you receive a certain number of points (or bucks or “dollars”) for the stuff you give away and can use that virtual currency to “buy” things you want.

Some sites require you to pay a transaction fee for using the site. Shipping is handled a bit differently by each site; some have flat shipping rates, some have the sender pay for the item to be sent, others use PayPal accounts to cover mailing costs or leave it to users to figure out how they want to handle things.

Some Web sites, such as U-Exchange. com/BarterServices and Craigslist.org, allow people to trade services and skills they can offer for work, services or items they need.

There are specialty swap sites, too, in case you are looking for something specific, like books (PaperbackSwap.com, Unlibrary.com and FrugalReader.com), video games (iTradeVideoGames.com), clothes (SwapStyle.com, DigNSwap.com, BigWardrobe.com), and even makeup (MakeUpAlley.com).

Did you see that movie “The Holiday” with Cameron Diaz and Kate Winslet? For two weeks during Christmas, Cameron swaps her sleek Los Angeles pad for Kate’s cozy English cottage.

You can really do that at HomeExchange. com! Only in real life, there’s a listing fee of $99.95 to use the site, and there’s no guarantee you’ll meet and fall in love with Jude Law.