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.
Bartering does have its limitations. Many bigger (i.e., chain) businesses will not entertain the idea and even smaller organizations may limit the amount of goods or services for which they will barter (i.e., they may not agree to a 100% barter arrangement and instead require that you make at least partial payment). But in an economic crunch, bartering can be a great way to get the goods and services you need without having to pull money out of your pocket.
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.
Variable Merchant Gold - Adds more gold to select merchants. Merchants in major cities will no longer have the same amount of gold as their small-town counterparts. There are three levels with increasingly greater difference between the gold amounts for city & small town merchants. Personally, I would recommend leaving the Base Merchant Gold at vanilla values and choosing one of the Variable settings instead. You can stack the Variable settings by selecting multiple options in order to get even greater increases in merchant gold, but I really don't recommend doing this as I haven't balanced the values with this intention.
In Spain (particularly the Catalonia region) there is a growing number of exchange markets. These barter markets or swap meets work without money. Participants bring things they do not need and exchange them for the unwanted goods of another participant. Swapping among three parties often helps satisfy tastes when trying to get around the rule that money is not allowed.
The same thing holds true of all other possessions; for barter, in general, had its original beginning in nature, some men having a surplus, others too little of what was necessary for them: hence it is evident, that the selling provisions for money is not according to the natural use of things; for they were obliged to use barter for those things which they wanted; but it is plain that barter could have no place in the first, that is to say, in family society; but must have begun when the number of those who composed the community was enlarged: for the first of these had all things in common; but when they came to be separated they were obliged to exchange with each other many different things which both parties wanted.