What ain't there and ought to be.

[Gurthang]

I don't have the Hobbit with me right now, but is there anything in there describing Smaug's hoard as having coins in it? I know it's gold and jewels, but is the gold in monetary form?

But also there must have been money in the Shire, because Bag End and everything in it were being auctioned off when Bilbo returned from his adventure. It wouldn't make sense that they traded something for Bilbo's possessions, as the whole point of the auction was to liquidate all the assets. Surely money is implied in this situation, if not exactly said to be.