Suppose Nellie decides to take a trip to Tennessee. Which result would be a cost?

 - Nellie will give up the chance to go to Maryland. She would have enjoyed a trip to Maryland more than Tennessee.
 - Nellie will save some money. Plane tickets for Nellie to get to Tennessee are less expensive than tickets to Maryland.
This result is a cost. It involves giving up or spending something that Nellie wants or needs:
Nellie will give up the chance to go to Maryland. She would have enjoyed a trip to Maryland more than Tennessee.