In his analysis of barter between coastal and inland villages in the Trobriand Islands, Keith Hart highlighted the difference between highly ceremonial gift exchange between community leaders, and the barter that occurs between individual households. The haggling that takes place between strangers is possible because of the larger temporary political order established by the gift exchanges of leaders. From this he concludes that barter is "an atomized interaction predicated upon the presence of society" (i.e. that social order established by gift exchange), and not typical between complete strangers.
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.
Bartering services is best reserved for when you were going to make a purchase anyway. So instead of bartering your dog grooming services for an emergency plumber, you could establish an agreement with your shampoo supplier. You know you're going to need shampoo to run your business. So offer to perform a pet pedicure in exchange for an equal value of shampoo each month.
Identify your resources. What items do you have that you could easily part with? Use a critical eye to go through your home, and consider possessions you may have in storage or that another family member or friend is currently using. If you would prefer to offer services, honestly assess what you could provide for others that they would otherwise pay a professional to do. It could be a skill or a talent or hobby such as photography.
I wish I came up with this fantastic idea. SharedEarth is a free site that connects landowners with gardeners and farmers in need of space to grow crops (i.e. starting a home vegetable garden). You can find free access to land in exchange for sharing a little bit of produce with the landowner. In a time of a strong and growing local food movement and concerns about food safety, SharedEarth might just be the most important sharing site of all!