Adjust barter rates to suit your tastes. Do you want to make it more difficult to accumulate vast amounts of money from selling items? Do you want to decrease the effect that your Speech skill has on prices and lend some extra importance to the Speech perks? However, this is one of the features that can conflict with other mods, so if you don't want Trade & Barter to override the values set by another mod, simply make sure this feature is deselected. By default, it is already deselected.
As Orlove noted, barter may occur in commercial economies, usually during periods of monetary crisis. During such a crisis, currency may be in short supply, or highly devalued through hyperinflation. In such cases, money ceases to be the universal medium of exchange or standard of value. Money may be in such short supply that it becomes an item of barter itself rather than the means of exchange. Barter may also occur when people cannot afford to keep money (as when hyperinflation quickly devalues it).
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.