How much did serf peasants in the middle ages pay to keep their house?

If they were serfs they worked for the Manse, that is the person that owned the land. Their homes were owned by the Manor as well. Money was seldom used. Their shelters were usually shared with animals. The exchange for goods was usually bartering, that is, they would perform a task for someone and get paid by the person they performed the task for with a service or another good. Some had small gardens in order to survive, but often had to turn over a certain portion of their crops to the Manor as a form of tax. Serfs were in many instances slaves having nothing of real value that they could exchange for money. Wars were often waged between manors and as individuals began to acquire more and more manors they began to let others govern their manors. Out of this persons began to become specialists in certain tasks, such as blacksmiths, tanners,wheelrights, carpenters etc. Then these specialists began to receive pay for their efforts, but they were no longer serfs.