Suppose Juan decides to bake coffee cake muffins. Which result would be a cost?

 - Juan will get to eat more muffins. He can make more coffee cake muffins than apple muffins.
 - Juan will give up the chance to eat apple muffins. He thinks apple muffins are tastier than coffee cake muffins.
This result is a cost. It involves giving up or spending something that Juan wants or needs:
Juan will give up the chance to eat apple muffins. He thinks apple muffins are tastier than coffee cake muffins.