Gold, otherwise known as money, is the currency used in the Bard's Tale universe.
In the first installment, money is scarce amongst any starting party. What little there is must be used to scrape together some rudimentary armor and weaponry in order to survive the harsh encounters in Skara Brae. Any money that is won from initial encounters is typically used either on healing temples or acquiring more armor/weaponry (or both). As time goes on and the party grows stronger money accumulation becomes quite easy, with the highest expense generally being paying approximately 14000 coins to resurrect a dead character or restore a level that was drained from a character.
The second Bard's Tale game is also fairly difficult to get going money-wise with a starting party, as again the party struggles to afford basic equipment and the costs of healing from encounters. It is worth noting that the game will not record a character's money on hand once they are loaded into the party; i.e. if the computer should be restarted for whatever reason without saving the character back to disk their money will be reset to zero. To compensate for this, there is Bedder's Bank for the Bold which allows players to deposit money in multiple accounts.
In Bard's Tale III, the money system is largely downplayed as almost inconsequential. There are still fees for providing healing services, and The Old Man will charge spellcasters fees for learning spell levels (as will the Review Board from the previous two games), but beyond this all that is required is money to learn the three mystery spells along the way and the two extra bard songs.