IDIOMS

arm and a leg

(idiomatic) A very high price for an item or service; an exorbitant price; usually used after the verb cost.

Example: 1954, them, “her”[1], meCommentary, volume 18, American Jewish Committee, page 448:
  That Polack costs me an arm and a leg, he thought.
1960 March 29, “Slim Waists Prompted New Sportswear Line”, New York Times, page 44:
  Bangle bracelets in fourteen-karat gold that do not cost an arm and a leg are always in demand.
2008, Jackie Collins, Hollywood Wives[2], Pan Macmillan, ISBN 9780330462433, page 417:
  Her house was fabulous, her tits perfection – besides – the Beverly Hills Hotel was costing him an arm and a leg.