An Arm and a Leg
DEFINITION: We say something costs "an arm and a leg" if it is very expensive.

EXAMPLE: Geez! It's an arm and a leg to fill your gas tank nowadays!
"I finally finished the integration of your comments... I was really impressed how fast you could grasp the idea and use a more elegant way to express it."
Junjun Deng
Graduate Student
The University of Iowa