cost a pretty penny
cost a pretty pennyand cost an arm and a leg; cost the earth
Fig. to be expensive; to cost a lot of money. Mary's dress is real silk. It must have cost a pretty penny. Taking care of a fancy car like that can cost a pretty penny, let me tell you. It cost an arm and a leg, so I didn't buy it. A house that size with an ocean view must cost the earth!
cost (somebody) a pretty penny
to be very expensive That diamond ring must have cost him a pretty penny.