It kind of seems obvious when you stop and think about it: certain people have things they don’t need or want anymore and other people want those things. Since the technology exists for those people to connect and mutually benefit, shouldn’t we all take advantage of it? Because of this win-win scenario and some handy tools, swapping items via the internet has gotten hugely popular. You can swap just about anything online these days and save big doing it. Here are some sites to get your started:

Paperbackswap
Despite the name, this site specialized in trading all kinds of books. You start by listing books you don’t want anymore. Next you get a notification via email when someone has requested that you mail them one of your unwanted books. Each time you send a book – which usually costs around $3 – you get a credit to receive a book. You can create a wish list so that your desired books get sent automatically when they are available, or you can browse what other users have offered. The site makes it extremely easy to mail the books, letting you print a “wrap” with postage already printed on it.

Goozex
If computer games and movies are more to your liking, check out this site that allows you to trade according to the points you build up. It’s almost like a game unto itself. There is a transaction fee of $1.99 per trade, but as long as you have a strong feedback score from your previous trades, you get a 50% discount on the fee.

SwapStyle
As any fashionista can tell you, building a killer wardrobe can take a lot of bucks. SwapStyle lets you trade in your gently-used couture and pick out the new-to-you threads of your choice. A swap pioneer with origins going all the way back to 2004, the site has earned a large following and with it a sizeable inventory from which to choose.

Swapmamas
No one knows better than mothers how quickly items can be outgrown. This mom-powered site hooks up those who have too-small goods with those for whom the exact same item is just right. But it’s not just clothes. You can find almost anything you need for bringing up baby.

Freecycle
If there were just one phrase to capture the beauty of this site, it’s this: “It’s pretty amazing what people are willing to just give away.” Whether it’s TV’s, furniture, coffee makers or old National Geographics, you’ll be surprised by what you can get for nothing more than the cost of going to pick it up. The site also lets you request specific items from people in your area.

Neighborrow
Does everyone on your block really need to own a belt sander? Unless you live in your city’s Wood Finishing District, the answer is probably “no.” But there are times when you might need one. Neighborrow lets you create or join a collective in your area to loan out and borrow non-everyday items. While some tools are available only for a rental fee, you will still likely be able to save a great deal over what you would pay renting from a large chain.