How much did a knight's armour cost in 1350?
The record: £16 6s 8d, 1374.
About $48,000 in today's gold
8 years of a farm labourer's pay.
All the armour in one knight's inventory, probably mail with plates; the helmet alone was 13s 4d. Source
Who could buy it
The lowest paid on each ladder of 1350 whose pay was enough:
In other words, out of a farm labourer's reach: more than a whole year of his pay.