EN World has been pushing this Fantasy Money thing hard, billing it as the ultimate gaming accessory. Essentially, fantasy money is a bunch of bills in denominations like 5cp or 100gp or whatever. It is Monopoly money for D&D.
This strikes me as the worst idea ever.
Part of it is that I don't like to worry about piddly sums of funds in most of my D&D games. If my character is relatively wealthy, I'd prefer to not worry about anything with a negligible cost. If the cost is negligible, I'm going to ignore it. I don't want to have to trade in a 1,000 gp bill and get change so I can spend 10 cp. That is a lot of pointless busywork.
Moreover, I can tell you... I have enough trouble keeping track of my character sheets. For a lot of games, I just print out a new one each session. I certainly don't want to have to keep track of where I've stashed a pile of bills.
Lastly, I don't even see what this accomplishes. How is passing bills back and forth (and making appropriate change) any easier than keeping a running total on the back of your character sheet?
Okay, it might not be the worst idea ever. There are a lot of really bad ideas out there, like the $1,000 ice cream sundae. I suppose this is a better idea than that...