Answer:
Good Faith
Step-by-step explanation:
Based on the information provided within the question it can be said that the concept being mentioned is called Good Faith. In the context of business contracts this term refers to both parties that enter into a contract together dealing with each other honestly and fairly. Keeping the contract price at a fixed price is part of this since, it allows both parties to know how much one is paying and the other is receiving, if the price is able to fluctuate it can blindside the other party and cause problems or misunderstandings.