Honestly, I don't think most people did that kind of complex bartering. Leave that to the merchants.
How can a merchant operate without some kind of abstract means of indicating value?
Being a merchant means you can estimate value.
Ex:
Merchant knows that Appleville has lots of apples but almost no pigs.
Merchant also knows that pig town (a few days trip) has lots of pigs. He also knows that their apple pie festival is next week.
So the merchant will get apples and trade them for pigs which he will then trade for more apples. Or vice versa.
As a merchant he knows the supply and demand of the area he peddles so he can anticipate who would buy what.
Sometimes he wins, sometimes he loses.