Before answering this question, I want to note that buying wasn't the only way to get into the comfort of wearing chainmail. You could also inherit, rent it or take mail from an enemy. Given the longevity of chainmail, I bet that buying is overrated. Here are some records of what people spent on chainmail: 1000 Germany: Mailarmor costs 820 silver coins. A cheap cow is 100. 12th-century England: Mail is 100 shillings, a warhorse 50, a cow 10. 13th-century Scandinavia: A good cow equals 12.3 kg of iron ingots. 1322 England: A hauberk costs 10 marks. A mantle costs 1 mark. 1324 England: A haubergeon costs 10 marks. A tent costs 3 mark. Sources: [1] https://www.mittelalter-server.de/Mittelalter-Geld/Das-Mittelalter-Geld-im-Mittelalter_Preise.html [2] Frances Gies, The Knight in History, Harper & Row, New York, 1984, page 30 [3] Smith, K.P., Ore, Fire, Hammer, Sickle: Iron Production in Viking Age and Early Medieval Iceland Skre, D. (Chapter 3) Silver Economies, Monetisation and Society in Scandinavia, AD 800-1000 [4] South Lancashire in the reign of Edward II as illustrated by the pleas at Wigan recorded in Coram Rege Roll no.254 Page 111 [5] John France, Medieval Warfare 1000–1300. Further Reading: Table of Medieval Prices