The economy of the Middle Ages has been studied (here, for example: http://www.dartmouth.edu/~mkohn/orgins.html), and it had one distinguishing feature: there was no small coinage; the smallest denomination that people would generally accept was a day's wage.

One can guess how people dealt with this: they extended credit to each other. A village's general store served as its bank. Tools and workmen's boots had to be ultra-reliable. In generally, the economy back then looked surprisingly modern (Cicero talks about letters of credit in his letters, the risk in long-distance trade was spread by buying shares in a voyage), the only thing that was missing was advertising.