Minecraft wiki entry for Superflat_survival, associated text: Convert and cure zombie villagers to reduce the prices, making trades cheaper (especially enchanted books as you need them for enchanting). However, this is difficult and expensive because you need drowned (before 1.17) or zombified piglins to get gold. Weakening the zombie villager is dangerous as you need a witch. If you use the witch cage described earlier and have the pig farm and lightning rod, this becomes slightly easier. Make sure your armor doesn't have thorns because it can hurt the zombie villager.