Coins are not all that loved by many Heartlings of these days, but they can allow for an easier transfer of goods and services...
But there is always a few problems when coming to use coins.
1; There is no good way to store them, coin pouches have been mentioned before, but perhaps another look is warranted.
2; Anyone with a Coppermine and Coinpress can make their own money, this means that even if a city tries to maintain a economy, some person could easily come in with their own homemade coin and inflate the community.
My thoughts on making Coins that are printed with the symbol of the Village it belongs to would be a good method to clean up other coins brought into the city, Perhaps a Lawspeaker can take a Coinpress to the Idol or Charterstone and Link the press to the Village itself, then all coins printed with that Press are marked to be that Village's National Coin.
It is a loose idea, but perhaps someone can help me expand on my thoughts. Brodgar is nearly ready to start its own economy and I would love for it to be able to avoid these problems...