Do to the plague the economy suffered greatly. The plague not only devestated the population it also attacked plants and live stock. Since there were no plants or animals to eat and trade many died from hunger and alot suffered without. The lords,vassels, and kings suffered more mainly because they depended mostly on peasents for everything.
With so many people dead, the job market became a peasants dream. All at once they could name their own price and had cheaper rent. The nobles had to treat and pay more for the labor or peasants would just leave and go someplace different. The economy struggled at first, then became much more stable than before.