A quick google search gave me an estimate of a 300:1 cost ratio of iron to silver (1 lb iron costing ~300 lb silver) in the 14th century.
You have it inverted; your link says:
That is, a (pure!) silver pound would buy 300 pounds of iron or steel.
Whoops. My bad.
You have it inverted; your link says:
Whoops. My bad.