IDIOMS

give away the store

(idiomatic) To transact, trade, or negotiate badly, by paying, providing, or conceding too much to the other party.

Example: 1987, Thomas Griffith, "Newswatch," Time, 14 Dec.:
  But he left the impression he wanted, of a man prepared to be conciliatory who would never give away the store.
2006, Richard Wolf, "Congress poised to pass $70B in temporary tax cuts," USA Today, 11 May (retrieved 21 June 2009):
  "Bush's tax plan offers next to nothing to average Americans, while giving away the store to multimillionaires," said Senate Minority Leader Harry Reid.