Definition of "elevenpence"

Now the dealer was a young man, who did not know the ways of Castellybryn, and he was aware that the first dealer was a big buyer and a cunning bargainer; so he purchased the butter for elevenpence farthing a pound, being a farthing a pound above the market price of that day.

1915, Caradoc Evans, “A Heifer without Blemish”, in My People: Stories of the Peasantry of West Wales‎, New York: Boni & Liveright, published 1918, page 35