Food and prices are popular topics in medieval history research, possibly because both areas are so maddening and rife with uncertainties. If you’re trying for some amount of realism in your medievalist setting, a good starting point is Agriculture and Prices in England 1259-1400 by J. E. T. Rogers. (If you live anywhere near a college or a university in the U.S., even if you are unaffiliated, you usually can get a community library card. You can get access to a lot of good books through the interlibrary loan systems.)

To compile anything approximating a complete list of foods and prices, you literally need to pull from dozens of sources, but this book is a good starting source.

In England, and with some variance in other cultures and geographies, Rogers finds eight basic food categories: grain, meat, poultry, fish, eggs and dairy products, vegetables, fruits and spices, and ale and wine.

In this PDF, I listed some examples of specific foods and prices from his research. And many times, I only needed one specific piece of information to ground a part of my story in reality (e.g., one silver pence, plus or minus, could buy your character a gallon of ale).

I’ll expand on this issue over time. But Hunt and Murray’s A History of Business in Medieval Europe, 1200-1550 is another good source on food production and other industries.