Tolkien didn't deal with economics much, considering that he frequently had his characters stranded in the wilderness unable to get any. They wondered who funded it. (Though in the Appendices, we learned the dwarves did blacksmithy.) I did bring up how gold discoveries have often brought booms because they had economies that strained at the limit of the amount of coinage they had.
The usefulness of money as opposed to say sheep, how coins were debased because of the lack of gold, how bank notes were discounted according to reports of how solvent banks were in various periods in American history
Middle class or not. One panelist thought it was more modern, but I brought up the rich merchants of the middle of the Middle Ages. (You can tell when it happened because knights, instead of just being men who fought, started to be dubbed knights. The rich merchants had too much clout, you had to differentiate yourself -- and they thereby opened a great gap, because fighting is in fact a harder qualification than being dubbed.)
Some talk of good examples, none of which I remember also. I brought up Poul Anderson's "Fairy Gold" where it vanishes after making a lot of people happy by letting them unload a white elephant and get what they needed. It even comes back to the original hands.