Suppose Valentina decides to go as a superhero. Which result would be a cost?
Valentina will give up the chance to wear the costume she is more excited about. Valentina will save some time and money. She won't have to go out and get a new costume.
Valentina is deciding whether to go as a vampire or a superhero to a costume party. She would rather go as a vampire. But she already has a superhero costume.
Before you decide to do something, it is often helpful to list costs and benefits.
Costs are what you give up or spend when you decide to do something. Costs involve giving up things that you want or need.
Benefits are what you gain or save when you decide to do something. Benefits involve gaining something that you want or need.
This result is a cost. It involves giving up or spending something that Valentina wants or needs:
Valentina will give up the chance to wear the costume she is more excited about.