Answer:
Equilibrium price
Explanation:
Equilibrium price is the point at which the quantity a consumer is willing to buy is equal to the quantity a supplier is willing to sell at a particular price.
So in this case Clara is happy to buy the cup cakes at $2 and does so regularly. Sam is also willing to sell at $2.
This is exemplified in the attached diagram (P1).
If however Sam decides to increase the price above equilibrium, Sarah might go elsewhere to buy at a price she wants.