cost the earth
To be exorbitantly expensive. A: "Your new car looks pretty slick!" B: "I should hope so, it cost the earth!" The company is making cutting-edge smartphones that don't cost the earth for consumers.
cost (or charge or pay) the earth
cost (or charge or pay) a large amount of money. British informalcost/pay/charge the ˈearth
(British English, informal) cost/pay/charge a lot of money: It needn’t cost the earth to refurbish your offices.