Let's say that you want to make it more difficult to make a quick profit from the items you sell. So you decide to increase the barter settings to 10.0 and 6.5. At these settings, you will receive only 10-15% of an item's value (vanilla is 30-50%). However, you'll suddenly discover that the cost to purchase items has skyrocketed to 1000-650% (vanilla purchase costs are 330-200%). Maybe this is exactly what you want. If so, congrats, there's no need for you to mess with the Independent Adjustments. However, if you would like to reduce the purchase price to a more reasonable level, then you can use the Buying Prices adjustment to lower only the buying prices without affecting the selling prices.
STOLEN GOODS - Don't expect any favors from Fences. Selling stolen items is going to cost you, so don't expect to get top dollar for ill-gotten goods. Tonila is exempt (actually all Thieves Guild & Dark Brotherhood fences are exempt, but in the vanilla game this just applies to Tonila). Any mod-added merchants who have been made members of the Thieves Guild or Dark Brotherhood faction will also be exempt. Options: -25% to -5% worse prices.
Economic historian Karl Polanyi has argued that where barter is widespread, and cash supplies limited, barter is aided by the use of credit, brokerage, and money as a unit of account (i.e. used to price items). All of these strategies are found in ancient economies including Ptolemaic Egypt. They are also the basis for more recent barter exchange systems.
On paper, this sounds a bit like delayed barter, but it bears some significant differences. For one thing, it’s much more efficient than Smith’s idea of a barter system, since it doesn’t depend on each person simultaneously having what the other wants. It’s also not tit for tat: No one ever assigns a specific value to the meat or cake or house-building labor, meaning debts can’t be transferred.
Bartering is based on a simple concept: Two individuals negotiate to determine the relative value of their goods and services and offer them to one another in an even exchange. It is the oldest form of commerce, dating back to at time before hard currency even existed. (Learn more about how bartering evolved, read The History of Money: From Barter To Banknotes.)
PERKS - Trade & Barter allows you to adjust the value of the Investor and Master Trader perks. This should work even if you have another mod that alters the Speech tree. Options: set either perk to 5000 max. You can set independently adjust the amounts required to invest and the amount of gold the merchant receives. However, when you make the initial investment, this money will be available until spent. Trade & Barter also adds to the Investor Perk by providing merchants with increased inventories when you invest in them. Increased inventories are unique to each individual merchant.
Check online swap markets and online auctions that have a bartering component such as Craigslist.com (check under "For Sale" for the Bartering category), Swapace.com, SwapThing.com, Barterquest.com, U-Exchange.com, Trashbank.com and Ourswaps.com. Check for local bartering clubs. Your local Chamber of Commerce may be able to provide you with information on similar clubs in your area.
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).
Barter, the direct exchange of goods or services—without an intervening medium of exchange or money—either according to established rates of exchange or by bargaining. It is considered the oldest form of commerce. Barter is common among traditional societies, particularly in those communities with some developed form of market. Goods may be bartered within a group as well as between groups, although gift exchange probably accounts for most intragroup trade, particularly in small and relatively simple societies. Where barter and gift exchange coexist, the simple barter of ordinary household items or food is distinguished from ceremonial exchange (such as a potlatch), which serves purposes other than purely economic ones.