1. I really wanted that painting, but it cost a mint , so I decided not to buy it
2. Sending my son to that college will cost me an arm and a leg, but it will be worth it.

Compare to: pay through the nose. The expression suggests that something costs all the money stored in a mint—a place where money is coined—or that something costs the same value as someone’s arm and leg. Unlike pay through the nose, these two expressions are used for monetary payments only.