The New York Post's unions offered to sacrifice 116 jobs over three years in a $33-million cost-saving plan aimed at preventing owner Rupert Murdoch from closing the tabloid Friday. Murdoch's representatives were to respond to the proposal today. Murdoch said he would stop the presses unless the unions agree to $24 million in salary and staff cuts. His sale of the newspaper to real estate developer Peter Kalikow for $37 million is contingent on the unions' acceptance of the cuts. Under the cost-saving plan, the newspaper would save $19 million over three years by reducing the staff by 116 employees. The plan also proposes cuts in bonuses and overtime totaling $14 million. In return, the Post's remaining union workers would receive wage increases.