Economists since the times of Adam Smith (1723-1790), looking at non-specific pre-modern societies as examples, have used the inefficiency of barter to explain the emergence of money, of "the" economy, and hence of the discipline of economics itself. However, ethnographic studies have shown that no present or past society has used barter without any other medium of exchange or measurement, nor have anthropologists found evidence that money emerged from barter, instead finding that gift-giving (credit extended on a personal basis with an inter-personal balance maintained over the long term) was the most usual means of exchange of goods and services.
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.
If you live in a major metropolitan area, chances are that you probably take public transportation to most of your destinations. You ditched your car long ago – eliminating parking, gas, and car insurance from your budget. But what if you need to get out of town for an hour-long meeting or pick up 25 bags of dirt from the landscaping store? Do you rent a car for the whole day even though you only need it for a few hours? Not if you have Zipcar nearby.
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.