The control the Church had over the people was total. Peasants worked for free on Church land. This proved difficult for peasants as the time they spent working on Church land, could have been better spent working on their own plots of land producing food for their families.
They paid 10% of what they earned in a year to the Church (this tax was called tithes). Tithes could be paid in either money or in goods produced by the peasant farmers. As peasants had little money, they almost always had to pay in seeds, harvested grain, animals etc. This usually caused a peasant a lot of hardship as seeds, for example, would be needed to feed a family the following year. What the Church got in tithes was kept in huge tithe barns; a lot of the stored grain would have been eaten by rats or poisoned by their urine. A failure to pay tithes, so the peasants were told by the Church, would lead to their souls going to Hell after they had died.
This is one reason why the Church was so wealthy. One of the reasons Henry VIII wanted to reform the Church was get hold of the Catholic Church's money. People were too scared not to pay tithes despite the difficulties it meant for them.
You also had to pay for baptisms (if you were not baptised you could not go to Heaven when you died), marriages (there were no couples living together in Medieval times as the Church taught that this equaled sin) and burials - you