In the United States, Karl Hess used bartering to make it harder for the IRS to seize his wages and as a form of tax resistance. Hess explained how he turned to barter in an op-ed for The New York Times in 1975. However the IRS now requires barter exchanges to be reported as per the Tax Equity and Fiscal Responsibility Act of 1982. Barter exchanges are considered taxable revenue by the IRS and must be reported on a 1099-B form. According to the IRS, "The fair market value of goods and services exchanged must be included in the income of both parties."
Just as with most things, there are disadvantages and advantages of bartering. A complication of bartering is determining how trustworthy the person you are trading with is. The other person does not have any proof or certification that they are legitimate, and there is no consumer protection or warranties involved. This means that services and goods you are exchanging may be exchanged for poor or defective items. You would not want to exchange a toy that is almost brand new and in perfect working condition for a toy that is worn and does not work at all would you? It may be a good idea to limit exchanges to family and friends in the beginning because good bartering requires skill and experience. At times, it is easy to think the item you desire is worth more than it actually is and underestimate the value of your own item.
It’s hard to answer that without actually seeing a modern gift economy in action. Luckily, modern gift economies actually do exist. On a small scale, they exist among friends, who might lend each other a vacuum or a cup of flour. There’s even an example of a gift economy on a much larger scale, albeit one that’s not always in operation: The Rainbow Gathering, an annual festival in which about 10,000 people gather for a month in the woods (it rotates among various national forests around the country each year) and agree not to bring any money. Groups of attendees set up “kitchens,” in which they prepare and serve food for thousands of people every day, all for free. Classical economists might guess that people would take advantage of such a system, but, sure enough, everyone is fed, and the people who don’t cook play music, set up trails, teach classes, gather firewood, and perform in plays, among other things.