Have you done any comparative economics? That is where you take what it "cost" in terms of money for goods or services at a given time and compare that to the cost of the same (or equivalent) goods and services in the present time. Some things like property ownership won't work because the rules changed so much between then and now but meals? Etc? might work.
Picking the 'BigMac index' might be fun, ie you try to price a Big Mac. (Since the Big Mac doesn't contain any tomatoes, you could probably have made a reasonable Big Mac clone in the Middle Ages.)
It gets ridiculous, if you go by the price of eg the amount of computation a human can do in a year. Or 'ice cubes in the height of summer'.
I could certainly see that. Now I'm wondering what someone would have bought with these pennies when they were actually coin of the realm.
Edit: per an up level comment, 15 chickens or half a knife? Hmm, chickens are easy the knife isn't. (wide variability in knife pricing). Given that the 'collectible' value has increased beyond the monetary value.
