Some quick numbers from 'The Army of Flanders and the Spanish Road' by Geoffrey Parker: "In the 1590s a pike and body-armour cost 30 florins, a musket cost 10 florins and a 24-pounder cannon cost 1000 florins." The armour cost the equivilent of bread for the wearer for a year. It is worth noting that the cost of the musket was a third of the cost of the pikeman's equipment - part of the reason the shot armed soldiers made up more than 2/3rds of most European infantry in the late medieval/early moden period.
The further back in time you go the greater the cost of equipment as a proportion of disposable income. Clear indication of the of the sort of equipment early medieval levies carried can be gleaned from the Bayeux tapestry. The Saxon fyrd are armed with shield and spears but no armour. The quality of the equipment of the lower class soldiers improved throughout the medieval period as states gained greater incomes, manufacture became cheaper and the armies became more professional. This process was neither uniform nor continuous but hold fairly well as a general statement.
