If you experience odd or unexplained amounts of merchant gold, even after the merchant has restocked, then you probably have another mod loaded after Trade & Barter which has altered the VenderGold leveled lists. To resolve the issue either: 1) Change the load order, and make sure that Trade & Barter loads after the other mod, or 2) Click the "Disable Merchant Gold Options" option from the menu. This will reset the Merchant Gold options and allow the changes from the other mod to prevail without further interference from Trade & Barter.
Some businesses that may not directly barter with customers may swap goods or services through membership-based trading exchanges such as ITEX or International Monetary Systems (IMS). By joining a trading network (which often charges fees), members can trade with other members for barter "dollars." Each transaction is subject to a minimal fee; the exchange facilitates the swap and manages the tax components of bartering such as issuing 1099-B forms to participating members. You may find a nearby exchange through the International Reciprocal Trade Association (IRTA) Membership Directory. Before you sign up and pay for a membership, however, make sure that members offer the types of goods and services you need. Otherwise, you may find yourself with barter money or credit that you cannot use.
There are several disadvantages of the barter economy. Firstly, there has to be double coincidence of wants for exchange to take place. Again the problem of indivisibility of commodities comes in the matter of exchange. Basically such disadvantages and many more called for the emergence of money. Money is used as a common medium of exchange and store of value.  

David Graeber argues that the inefficiency of barter in archaic society has been used by economists since Adam Smith to explain the emergence of money, the economy, and hence the discipline of economics itself.[2] "Economists of the contemporary orthodoxy... propose an evolutionary development of economies which places barter, as a 'natural' human characteristic, at the most primitive stage, to be superseded by monetary exchange as soon as people become aware of the latter's greater efficiency."[3] However, extensive investigation by anthropologists like Graeber has since then established that "No example of a barter economy, pure and simple, has ever been described, let alone the emergence from it of money; all available ethnography suggests that there never has been such a thing. But there are economies today which are nevertheless dominated by barter."[4]
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This mod alters the "VendorGold..." leveled lists that determine merchant base gold. It also alters the "PerkInvestor..." leveled lists. If you are using any other mod that alters these leveled lists then you will need to decide whether to load it before or after Trade & Barter. If Trade & Barter is loaded last, then it will overwrite any changes made by other mods to these leveled lists. If the leveled list changes from Trade & Barter get overwritten, then the merchant gold options & the "Inventory Changes when Invested" will likely not work.  

There might come a time in your business's life when you want to barter your services. In fact, you may find it prudent from time to time to trade your services for the services that another business offers. It helps to have a plan in place for this and to have some safeguards against overextending your services beyond what you can support. After all, if you barter all of your services all of the time, then you'll never earn an income.

MERCHANT GOLD - Trade & Barter gives you the option to set higher base gold amounts for each of the different vendor types.If you have another mod that alters the "VendorGold" leveled lists then you will have to decide if you wish to load Trade & Barter before or after the other mod. In most cases, I would recommend loading Trade & Barter after the other mod to take advantage of the flexibility and options provided by Trade & Barter. However, some mods, such as Economics of Skyrim, should be loaded AFTER Trade & Barter, so that this mod does not overwrite their changes.
With 8.5 million members and 5,000 groups, Freecycle is like the mother of all garage sales, with one exception: Everything is free! The site started as a grassroots organization, encouraging members to reuse products rather than send them out to the landfills. For example, I have used Freecycle many times to find new owners for pieces of my cassette and record collection, piles of magazines and books, and assorted unneeded tools.
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).[15]