Not necessarily a bad thing, as prices weren't regulated to be inflexible either. In response to merchant abuse, adulteration and fraud a whole slew of measures

Not necessarily a bad thing, as prices weren't regulated to be inflexible either. In response to merchant abuse, adulteration and fraud a whole slew of measures evolved, including the 1266 Bread and Ale Assizes. The court assizes were responsible for setting the fair price which both took into account supply and demand, and local variation, and for sampling the goods produced. This was not a national economy, the "right" price for ale or grain could vary just a mile or two down the road, or in the next valley over, subject to local weather and harvests. Which is why the local assize courts controlled it. One of the other interesting things was bread and some other foods adjusted to supply and demand by changing weight not price. Each assize set the current right weight of a farthing loaf. A standard weight loaf came much later, in the 19th century! There were also aletasters, breadmasters and a whole variety of others who would engage in sampling, and sometimes use of secret shopping, to ensure the local merchants for a particular good were producing quality, weight and not adulterating. What is less clear is whether they took their role seriously or whether it was a sinecure for free food and beer. The fines seem, in some regions, to have often been small and arbitrary, and it was often all under the auspices of the manor. Was it a valuable piece of Medieval regulation, or corruption? Well, going on how the Assizes of Bread and Ale played out, there was ample opportunity for local corruption and arbitrary fees. https://en.wikipedia.org/wiki/Assize_of_Bread_and_Ale https://en.wikipedia.org/wiki/Assize_of_Bread_and_Ale