Cost can refer to two things:
- The action token cost of a card, which is how many action tokens it takes for a player to play a card from their hand. This cost can be raised/lowered through game text. The cost to play a card cannot go below 0. Only friends, events and resources have an action token cost.
- Certain cards and the actions a player can perform during their Main Phase each have their own costs to use, which can include things such as paying action tokens and exhausting cards.