Suppose Grayson decides to make tomato soup. Which result would be a cost?

 - Grayson will save some time. The egg drop soup would have taken longer to make than the tomato soup.
 - Grayson will give up the chance to eat the egg drop soup, which would have been tastier than the tomato soup.
This result is a cost. It involves giving up or spending something that Grayson wants or needs:
Grayson will give up the chance to eat the egg drop soup, which would have been tastier than the tomato soup.