Then again, it’s one thing to keep a community alive and well when everyone’s camping in a forest and they’ve all opted in to that vision. It’s quite another to imagine a gift economy enabling humans to build skyscrapers, invent iPhones, put air conditioners in every house, and explore space. (The same goes for collecting taxes and running large businesses.) Not that it’s an all-or-nothing situation: We already have gift economies among friends and family. Perhaps expanding that within small communities is possible; it’s certainly desirable.
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.
Can you make home or vehicle repairs?  Do you manufacture pieces that may be needed for repair?  Can you grow fruit and vegetables and gather the seeds to sell?  Do you sew, knit and repair clothing?  Think through what you can do.  Many skills that preppers have are taken for granted by others.  The skills that you have that seem like common sense to you could keep you and your family fed in hard times.
Barter, also known as counter-trade, is an accepted practice that makes trading more convenient for nations that have difficulty with currency conversion, as well as for nations with fewer financial resources but sufficient commodities. For example, if a country produces plenty of rice, that country may exchange it with another nation to acquire another type of grain, or fruits and vegetables. On the other hand, one country might trade foodstuffs for textiles or oil.
An online swap meet of sorts, at there is no bidding or money exchanged. Rather, you offer to trade the stuff you no longer want. You’ll then have the ability to choose from books, movies, CDs, and other items. The site doesn’t seem to have monthly charges, but you’ll be responsible for shipping costs associated with items you sell. Swap has its own free iPhone app for simple listing and searching.
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.[3] 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.[4]
The Internet has provided a medium for new growth in the bartering industry. This growth prompts the following reminder: Barter exchanges are required to file Form 1099-B.pdf, Proceeds From Broker and Barter Exchange Transactions, for all transactions unless an exception applies. Refer to Bartering in Publication 525, Taxable and Nontaxable Income, and the Form 1099-B Instructions, for additional information on this subject. Persons who don't contract with a barter exchange or who don't barter through a barter exchange but who trade services, aren't required to file Form 1099-B. However, they may be required to file Form 1099-MISC.pdf, Miscellaneous Income. Refer to the Form 1099-MISC Instructions to determine if you have to file this form. If you exchange property or services through a barter exchange, you should receive a Form 1099-B. The IRS also will receive the same information. 

While some people may balk at an online community for finding babysitters, I know several parents who say it’s actually very difficult to find a sitter they can trust. BabysitterExchange started in 2000 as a babysitting co-op, and it has since expanded to the point that members use it to reserve time when they just have some errands run, need help tutoring their kids, or want a temporary house-sitter.