I was recently directed to the Account Roll of the Priory of the Holy Trinity, Dublin (1337-1346) (thanks, Johnnae!). It's a book of household accounts for a monastery in medieval Ireland.
The neat thing about household accounts is that they contain a huge amount of information about what was needed for daily life. This particular book of accounts is in Latin, but (happily for me) also has an English translation. While browsing through it, I saw a decent number of food items listed, along with the priced paid for them. This led to the inevitable digging through data and taking notes.
Unfortunately, most of the entries specify what was purchased, the amount paid, and who the money was paid to, but not the actual quantity purchased. Still, there were some scattered about that included quantities. So below are the prices of select items for medieval Ireland, as per this manuscript.
capon (cooked), 3d/ea.
fowl (cooked), 2d/ea.
lamb (cooked, whole), 4d/ea.
oats (for horses), 2d/peck
olive oil, 6d/qt.
pasties (fowl), 2d/ea.
pasties (salmon), 1d/ea.
salt, 3d/peck (approx. 0.12d/lb.)
wine (by the tun), 1d/gal.
wine (red?), 5d/gal.
wine (white), 6d/gal.
There were also some records for amounts paid to laborers, which work out to have unskilled workers paid around 2d per day.
What I found really interesting is how a few of these compared to the prices listed in "Spices and Their Costs in Late-Medieval and Early-Modern Europe" by Prof. John H. Munro, University of Toronto. The prices for capons, red wine, and pepper were essentially the same - somewhat surprising given that we're comparing 14th century Dublin to 15h century London. The difference in the price of salt is also surprising - with London's price being roughly 5 times what it is in Dublin a hundred years earlier.