With 70,000 members posting items they would like to barter with or for, there is a good possibility you can find what you are looking for at U-Exchange. Listings are available from all over the world, and the search feature lets you narrow down your choices by keywords. There is no charge for membership or listings, as advertisers pay to sponsor the site.
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.
No academics I talked to were aware of any evidence that barter was actually the precursor to money, despite the story’s prevalence in economics textbooks and the public’s consciousness. Some argue that no one ever believed barter was real to begin with—the idea was a crude model used to simplify the context of modern economic systems, not a real theory about past ones.
To try a time bank, search online for one in your local area using TimeBanks.org. 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.
Communities of Iroquois Native Americans, for instance, stockpiled their goods in longhouses. Female councils then allocated the goods, explains Graeber. Other indigenous communities relied on “gift economies,” which went something like this: If you were a baker who needed meat, you didn’t offer your bagels for the butcher’s steaks. Instead, you got your wife to hint to the butcher’s wife that you two were low on iron, and she’d say something like “Oh really? Have a hamburger, we’ve got plenty!” Down the line, the butcher might want a birthday cake, or help moving to a new apartment, and you’d help him out.
Make the deal. After you've found a barter partner, get the agreement in writing. Make sure you detail what services or goods will be involved, the date of the exchange (or work to be done) and any recourse if either party reneges on their part of the deal. If you are working through a membership-based bartering association, they will likely provide all the structure and paperwork you need for the deal.
In a small economy where individuals specialize in trades, they may find the process of setting up a centralized currency and maintaining it an unnecessary burden in order to trade. One option may be to use a commodity to exchange value between parties that want to trade goods or services and this is why gold and silver have been useful forms of currency in many cultures and times. Another option may be to use a barter system to trade.

So as you consider items to stockpile, you should think about items that are necessary, but might not take up a lot of space.  Referring back to Mark Goodwin’s book mentioned above, one thing the main characters looked for were canning lids and rings.  They don’t take up a lot of space and in a real collapse situation, they will be really worth it!
And that means everything from tuna to stamps to cigarettes has its own unique value in a trade and barter market. — Alexandra Cardinale, Vox, "Why ramen is so valuable in prison," 14 Nov. 2018 European officials were also looking at a barter system that would allow Iran to sell oil, for example to China, and use the proceeds from that sale to purchase goods or technology from Europe. — Laurence Norman, WSJ, "Europe’s Payment Channel to Salvage Iran Deal Faces Limits," 25 Sep. 2018 With unemployment around 9 percent and consumer prices surging, some Argentines are again turning to barter clubs, which first emerged during the collapse nearly two decades ago. — Almudena Calatrava, Fox News, "Argentines seek soup kitchens, barter markets amid crisis," 10 Sep. 2018 This particular search insired Gellar and Laibow to hop on the phone and barter. — Colleen Leahey Mckeegan, Marie Claire, "Sarah Michelle Gellar's Second Act? Disrupting the Food Industry," 18 Apr. 2017 Choco Pies became so prevalent for sale or barter on the streets that North Korea reportedly banned their import to Kaesong in 2014. — Brian Murphy, Washington Post, "The Choco Pie dividend: South Korean firms are drooling at the prospect of business in the North," 17 June 2018 In 1996, amid crippling famine, Ji tried to steal a few pieces of coal from a rail yard to barter for food. — Brian Murphy, BostonGlobe.com, "Could these outspoken North Korean defectors return home?," 11 June 2018 In 1996, amid crippling famine, Ji tried to steal a few pieces of coal from a rail yard to barter for food. — Brian Murphy, BostonGlobe.com, "Could these outspoken North Korean defectors return home?," 11 June 2018 Instead, like many early civilizations, they were thought to mostly barter, trading items such as tobacco, maize, and clothing. — Joshua Rapp Learn, Science | AAAS, "The Maya civilization used chocolate as money," 27 June 2018