The teenager lost a contact lens while playing basketball in his driveway.  After a fruitless search, he went inside and told his mother the lens was nowhere to be found.

Undaunted, she went outside and in a few minutes, returned with the lens in her hand.

"How did you manage to find it, Mom?" the teenager asked.

"We weren't looking for the same thing," she replied.  "You were looking for a small piece of plastic.  I was looking for $150."