Coins and Supplies are represented by the same tokens.
When these tokens are in a player’s area, they represent Coins.
When they are placed on cards, they are Supplies.
It is recommended to have them numbered-side up when they are Coins and Supply-side up when they are Supplies.
Coins are primarily used to pay costs of cards.
Supplies have different meaning depending on the card they are placed on:
Villagers - the amount of Supplies determine how many times they can be activated, before being Tucked.
Gear - similar to Villagers, Supplies determine how many times Gear cards need to be triggered, before resolving their Relic effects and getting Tucked.
Buildings - Supplies are placed through "Invest" abilities. Each Supply on a Bulding at the end of the game provides 1 victory point.