You’re probably right. I was just making up random numbers because I wanted Norn to appear knowledgeable about the values of the goods the Dwarves and Sindar are trading. I could just have him say that a dozen arrows would be worth the donkeys or the grain or the honey.I like it a lot , but one thing immediately sprung to my mind:
Four arrows for a sack
of grain. Ten for a jar of honey. Thirty-
five for a donkey.
Those seem damn low prices for arrowheads and damn high prices for donkeys and grain!
I think a dozen arrowheads for 2-4 donkeys are a realistic price, possibly less if we assume the dwarves produce very high quality, 12 arrowheads can also easily be 200-300 l grain, depending on type, quality and how great the need is.
I'd gladly try to research realistic prices for honey if you tell me how much one jar is in weight!