Back in the medieval times, it was exceedingly common to pay taxes in goods, plus do bartering. Random people living outside of towns didn't necessarily possess currency that much. In fact it could have been an unneccessary risk to have too much of it, even if they could, which they usually didn't since the vast majority of people were dirt poor. So, tax collectors would take an amount of crops, fur, wool, meat, dried fish, and such things, depending on the person's profession. If a person travelled once a year to a town, they might again exchange something they could sell for something they would need, such as salt. Or they might finally get some coins. After all, towns still liked to operate using money.