With over 40,000 listings in 142 countries, HomeExchange lists free places to stay almost everywhere in the world. Members pay just $9.95 per month to trade their homes and apartments with each other. After the monthly fee, your vacation lodging expenses won’t cost any more staying at home would. You’ll get to stay in a new place, while someone else comes to stay in your home, both free of charge.
In his analysis of barter between coastal and inland villages in the Trobriand Islands, Keith Hart highlighted the difference between highly ceremonial gift exchange between community leaders, and the barter that occurs between individual households. The haggling that takes place between strangers is possible because of the larger temporary political order established by the gift exchanges of leaders. From this he concludes that barter is "an atomized interaction predicated upon the presence of society" (i.e. that social order established by gift exchange), and not typical between complete strangers.
Stop lugging around old books you won’t read again and trade them for some new reading material instead. Bookmooch uses a points system, so you’ll enter the books you want to give away, get requests from members who want your books, ship from home, get points, and then spend the points on the books you need. While membership is free, you’ll receive .10 points for every book you make available and 1 point for every book you successfully give away. To remain in good standing, you need to give away one book for every two you receive.
For $75 per year, Capital Bike Share gives members access to inexpensive bike rentals around the Washington, D.C. area. Bike stations filled with 1,100 bikes are located all over the district and nearby towns, and a single membership key grants you access to use and return any of them wherever you are. The first 30 minutes are free, and each additional half hour costs a few bucks. Members can also use the SpotCycle app for the iPhone, Blackberry, and Android device to locate the closest available bike. You can also try a limited plan, like a 30-day pass for $25.