While it may be free, there is no one monitoring the barter ads, so you must be aware of potential Craigslist scams, and realize that you are always at risk when it comes to meetups and exchanges. For example, about a year ago, I arranged to trade massage gift certificates for housecleaning. Since the individual was coming to my home, I was more nervous than usual. However, she offered good previous references, and we  arranged for a time to meet when my husband would be home, in case an odd, unexpected, or even dangerous situation arose.
In late 2012, Toronto even got its own spinoff of Trade School, a model that originated in New York in 2010. The Toronto Trade School holds classes—on anything from spoken word to origami flower–making to bicycle maintenance—and invites students to “pay” with an item or service from the teacher’s barter wish list. It has hosted more than 70 classes.
Barter is a system of exchange by which goods or services are directly exchanged for other goods or services without using a medium of exchange, such as money.[1] It is distinguishable from gift economies in that the reciprocal exchange is immediate and not delayed in time. It is usually bilateral, but may be multilateral (i.e., mediated through barter organizations) and usually exists parallel to monetary systems in most developed countries, though to a very limited extent. Barter usually replaces money as the method of exchange in times of monetary crisis, such as when the currency may be either unstable (e.g., hyperinflation or deflationary spiral) or simply unavailable for conducting commerce.
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.
In recent years, barter has enjoyed a resurgence as a means of countering economic insecurity, unemployment and worker exploitation. The nature of modern-day work, the pervasiveness of the Internet and the rise of social networking have all contributed to its spread. Other examples of alternative economic systems include gift economies, sharing economies and time banks. 

The Internal Revenue Service (IRS) considers bartering a form of revenue and something that must be reported as taxable income. Under U.S. generally accepted accounting principles, or GAAP, businesses are expected to estimate the fair market value of their bartered goods or services. This is done by referring to past cash transactions of similar goods or services and using that historical revenue as a reportable value. When it is not possible to accurately calculate the value, most bartered goods are reported based on their carrying value.