Many prepper fiction novels eventually get to a point where there is a barter economy or the characters visit a Trading Post.  For instance, a trading post plays a prominent role in Mark Goodwin’s series, Seven Cows, Ugly and Gaunt: A Post-Apocalyptic Saga of America’s Worst Nightmare.  In the novel, the characters use silver to purchase the necessary items to survive and make life easier.  Goodwin’s novel is a post-apocalyptic EMP story.  The poop has really hit the fan in this one!
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.
Men from the visiting group sit quietly while women of the opposite moiety come over and give them cloth, hit them, and invite them to copulate. They take any liberty they choose with the men, amid amusement and applause, while the singing and dancing continue. Women try to undo the men’s loin coverings or touch their penises, and to drag them from the “ring place” for coitus. The men go with their … partners, with a show of reluctance to copulate in the bushes away from the fires which light up the dancers. They may give the women tobacco or beads. When the women return, they give part of this tobacco to their own husbands.
But in real-world scenarios, like in Venezuela, Greece, and Argentina,  the fabric of society is still intact.  Society hasn’t unraveled like it did for Selco in Bosnia.  In those countries, people still go to work (if they have a job), go to school and life goes on, although it really sucks!  In these cases, bartering will be a little easier, safer and more readily available as society is intact.

Barter exchanges have their own unit of exchange, usually known as barter or trade dollars.  Trade dollars or barter dollars are valued in U.S. currency for the purposes of information returns.   Trade dollars allow barter to take place between parties when one party may not have a simultaneous need or desire for the goods or services of the other members.  Barter exchanges act as the bookkeeper for keeping track of trade dollars that participants accumulate. Earning trade or barter dollars through a barter exchange is considered taxable income, just as if your product or service was sold for cash.
To try a time bank, search online for one in your local area using How time banks are managed varies according to the region, so it is important (and often mandatory) to attend an initial meeting that explains the general rules of your local chapter. Once you do this, you’re ready to start trading away. Your services and contacts are identified through the local time bank website.
@matthewc23 - I love being able to barter for things. You mentioned that you don't really have any specialized skills, but you would be surprised. Depending on your profession, think about any special training you have that a normal person wouldn't have. Some people would be willing to trade for that service. Even things you wouldn't normally think of as being services could be useful to someone else.

Whether or not one agrees with such broad claims, it’s worth noting that monetary debt, a byproduct of currency, has regularly been used to by some groups to manipulate others. Thomas Jefferson, for instance, suggested that the government encourage Native Americans to purchase goods on credit so they’d fall into debt and be forced to sell their lands. Today, black neighborhoods are disproportionately plagued by debt-collection lawsuits. Even after taking income into account, debt collection suits are twice as common in black neighborhoods as in white ones. $34 million was seized from residents of St. Louis’ mostly black neighborhoods in suits filed between 2008 and 2012, much of which was seized from debtors’ paychecks. In Jennings, a St. Louis suburb, there was one suit for every four residents during those years.